English

• The exploration of renewable energy sources is vital to relieve the environmental pollution and the increasing energy demands. Hydrogen gains much attention due to its sustainability, which can be electrochemically generated from splitting of water actuated by inconsecutive powers, wind and solar energies [1,2]. Proton exchange membrane water splitting (PEMWS) has been considered as the most encouraging water splitting technology for hydrogen generation attributing to its commercially available components [3,4]. As hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are the uphill reactions, requiring efficient electrocatalyst to drive, especially OER catalysis, rate limiting step for overall water splitting [5,6]. Besides, the stability also should be significantly weighed because of the harsh working condition, strong acid, high temperature and voltage, leading to a formidable challenge [7]. Ruthenium oxides (RuO₂) and iridium oxides (IrO₂) are the commercial OER electrocatalysts [8]; however, the stability as well as catalytic performance should be substantially enhanced to forward the industrialization of PEMWS. Additionally, more attention should be paid to RuO₂ because of its lower cost [9–11].

  The formation of *OOH specie is deemed as the rate-limiting step for acidic OER process, which forms via the nucleophilic attack by H₂O; thereby, the electrophilic property is highly recommended for the electrochemical absorbed *O species on active sites. Thus, the oxidation state of Ru should be lower than +4, favorable for the conversion of *O to *OOH leading to a boosted acidic OER performance [12–14]. Apart from catalytic activity, the low stability of RuO₂ originates from the low oxidation potential for forming high valance state of Ru, dissolvable in electrolyte. In this regard, the simultaneous promotion in catalytic activity and stability normally achieved by formation heterostructure [15,16], creating new material phase [17,18] and decoration with heteroatoms [19] since the electronic configuration of active sites, regulation in electrochemical adsorption-desorption of reaction intermediates, are effectively modulated and the forming energy associated with cohesive energy, fingerprint of stability, are reasonably adjusted [20]. Formation of heterostructure has the merits of boosting the OER performance, stability and reducing the dosage of noble metals, making this methodology a hopeful strategy for RuO₂.

  In this work, we have initially synthesized MIL-88B as template for the construction of RuO₂/V₂O₅ heterostructure with nanoneedle structure. More active sites were exposed in the nanoneedle structure and diffusion resistance was reduced; moreover, tip effect also contributed to a boosted catalytic activity. The overpotential at 10 mA/cm² was 216 mV for RuO₂/V₂O₅, which was decreased by 27 mV with relative to commercial RuO₂ due to more oxygen vacancies in RuO₂/V₂O₅ triggering a lower valance state of Ru, beneficial for the nucleophilic attack by H₂O, confirmed by the methanol. Besides, the OER performance tested under various pH indicated that the OER activity of RuO₂/V₂O₅ was more sensitive to hydrogen concentration indicating a better deprotonation capability. Moreover, the electronic interaction between RuO₂ and V₂O₅ efficiently increased the oxidation potential for Ru⁴⁺ resulting in a better stability, proved by the cyclic voltammetry test. The theoretical calculation revealed that the demanded energy for the formation of *OOH was decreased from 2.43 eV to 2.06 eV with incorporation of V₂O₅.

  As shown in Fig. S1 (Supporting information), the XRD pattern of the prepared MIL-88B showed intensive diffraction peaks at 17.5°, 25.2° and 28.0°, similar to the previous reports indicating the successful construction of MIL-88B. With the calcination temperature increased to 450 ℃, the V₂O₅ phase was obtained confirmed by its XRD pattern, in which diffraction peaks at 15.4°, 20.3°, 26.2°, 31.1° and 34.3° assigned to the (200), (001), (110), (400) and (310) crystal planes of V₂O₅ according to JCPDS No. 09–0387. As shown in Fig. 1a, the utilization of RuCl₃ as precursor, RuO₂–450 was formed verified by the diffraction peaks at 27.5°, 35.0° and 54.3° stemming from the (110), (101) and (211) facets of RuO₂ based on JCPDS No. 43–1027, similar to commercial RuO₂ [21]. The XRD pattern of RuO₂/V₂O₅ was resemble to that of V₂O₅, except the diffraction peak at 27.8° coming from the dominant (110) crystal plane of RuO₂; therefore, RuO₂ and V₂O₅ were both existed. To confirm the formation of heterostructure, XPS test has been carried out (Fig. S2 in Supporting information). The core-level Ru 3p peaks composed of Ru 3p_1/2 at 462.53 eV and Ru 3p_3/2 at 465.69 eV fitted to Ru³⁺ and Ru⁴⁺ species (Fig. 1b); interestingly, more Ru⁴⁺ species were noticed for RuO₂/V₂O₅ compared to that of RuO₂–450 demonstrating the electronic interaction between RuO₂ and V₂O₅. Besides, the high valance state was also underlined by the positive shift in binding energy. As shown in Fig. 1c, the V 2p_3/2 XPS peak was deconvoluted into two peaks centered at 517.11 and 516.60 eV, corresponding to V⁵⁺ and V⁴⁺ species, respectively [22]. A lower valance state of V atom was noted in RuO₂/V₂O₅. Thus, a heterostructure was found for RuO₂/V₂O₅ and Ru donated its electrons to oxygen atom from V₂O₅ resulting in a higher oxidation state compared to RuO₂–450 [23]. The higher valance state of Ru atom would be favorable for promoting the stability since RuO₂ was easily oxidized to Ru⁶⁺ species dissolved into electrolyte [24]. The presence of Ru valance state in RuO₂ would show a high resistance towards electrochemical oxidation under OER condition. As shown in Fig. 1d, lattice oxygen, oxygen defects and adsorbed H₂O composed of O 1s XPS spectrum [25,26]. It was found that oxygen defects in RuO₂–450 was higher than V₂O₅ and RuO₂, which would be harmful for the structural stability since the electrochemical oxidation occurred at defective sites [27]. Due to high percentage of oxygen vacancy, the O 1s peak of RuO₂–450 was negatively shifted with relative to V₂O₅ and RuO₂/V₂O₅.

  Figure 1

  

  Figure 1.  (a) XRD patterns of RuO₂/V₂O₅, RuO₂–450 and V₂O₅. (b) Ru 3p XPS spectra of RuO₂/V₂O₅ and RuO₂–450. (c) V 2p_3/2 XPS spectra of V₂O₅ and RuO₂/V₂O₅. (d) O 1s XPS spectra of RuO₂–450, RuO₂/V₂O₅ and V₂O₅.

  DownLoad: Full-Size Img PowerPoint

  As shown in Fig. S3 (Supporting information), MIL-88B exhibited a pine needle structure. However, the RuO₂–450 exhibited a microsphere structure. Due to the template of MIL-88B, nanoneedle structure was detected for RuO₂/V₂O₅ shown in Fig. 2a. The formed nanoneedle structure originated from the MIL-88B, serving as template. Differently, as shown in Fig. S4 (Supporting information), nanoparticle structure was recorded for commercial RuO₂. The TEM image shown in Fig. 2b also highlighted the nanoneedle structure of the formed RuO₂/V₂O₅. From the HR-TEM image shown in Fig. 2c, the lattice spacing of 0.33 nm and 0.44 nm originated from the (110) and (001) facets of RuO₂ and V₂O₅, respectively. Also, the relative Fast Fournier transfer (FFT) testified the presence of V₂O₅ (001) and RuO₂ (110). The HR-TEM image clearly showed the heterointerface indicating the formation of heterostructure. TEM test also underscored the formation of heterostructure in RuO₂/V₂O₅. The HAADF-STEM image shown in Fig. 2d implied the well-distributed Ru, O and V elements over the nanoneedle.

  Figure 2

  

  Figure 2.  SEM (a), TEM (b), HR-TEM (c), HAADF-STEM (d) and relative EDS mapping of RuO₂/V₂O₅.

  DownLoad: Full-Size Img PowerPoint

  The oxygen evolution reaction (OER) performance was estimated in 0.5 mol/L H₂SO₄. As shown in Fig. 3a, the synthesized RuO₂–450 exhibited an inferior OER performance with overpotential of 272 mV to reach 10 mA/cm², which was higher than the commercial RuO₂ (243 mV overpotential for 10 mA/cm²). RuO₂–450 showed an inferior OER activity to commercial RuO₂ due to its large particle size with less exposed active sites. However, with the introduction of V₂O₅, the overpotential at 10 mA/cm² was decreased to 216 mV for RuO₂/V₂O₅. Moreover, OER activity of RuO₂/V₂O₅ outperformed the benchmarked RuO₂. V₂O₅ performed an ultralow acidic OER performance with overpotential of 365 mV for 10 mA/cm², which was strong evidence for the boosted OER performance of RuO₂/V₂O₅ attributed to the reasonable modulation of electronic configuration of RuO₂. The OER performance of RuO₂+V₂O₅ was inferior to the counterpart of RuO₂/V₂O₅ emphasizing the heterostructure contributing to the boosted OER activity. The mass activity reached 11.6 A/mg_Ru for RuO₂/V₂O₅ at 1.53 V vs. RHE, boosted by 12- and 6-fold than RuO₂–450 and benchmark RuO₂ (Fig. S5 in Supporting information). As shown in Fig. 3b, Tafel slope was 45.87 mV/dec for RuO₂/V₂O₅, lower than RuO₂–450 (114.86 mV/dec) and RuO₂ (118.17 mV/dec). The lower Tafel slope indicates a faster acidic OER process [28]. Based on the Tafel slope, Eley-Rideal-like (ER-like) OER mechanism was observed for RuO₂/V₂O₅; while, the OER catalysis on commercial RuO₂ and RuO₂–450 followed Langmuir−Hinshelwood mechanism. As shown in Fig. S6 (Supporting information), charge transfer resistance (R_ct) was 102.6, 77.0 and 65.6 Ω for RuO₂–450, RuO₂ and RuO₂/V₂O₅, respectively. The lower R_ct was due to the formation of heterostructure with different work function for RuO₂ and V₂O₅ [29]; therefore, a built-in electric field was formed and electronic conductivity was promoted. The temperature dependent OER performance was tested (Fig. S7 in Supporting information) to calculate activation energy. As shown in Fig. 3c, the activation energy for RuO₂/V₂O₅ was dramatically decreased to 13.82 kJ/mol; while, this value was 19.53 kJ/mol for commercial RuO₂; thus, a better OER activity was achieved for RuO₂/V₂O₅. To quantitatively analyze the active center, double layer capacitance (C_dl) was estimated from cyclic voltammetry curves recorded under various scan rate (Fig. S8 in Supporting information). The C_dl values were 22.43, 7.46 and 49.07 mF/cm² for RuO₂, RuO₂–450 and RuO₂/V₂O₅ (Fig. 3d), respectively. Compared to RuO₂–450, C_dl of RuO₂/V₂O₅ was boosted by 6.6-fold by comparison with RuO₂–450. It is generally accepted that the adsorption of *OH species generated from water dissociation is important for the acidic OER, which can be detected by the nucleophilic methanol since *OH is considered as electrophilic reactant [30]. As shown in Fig. 3e, it was found that the current density was sharply increased at initial stage (below 5 mA/cm²) indicating the superb water dissociation capability of RuO₂/V₂O₅ to generate *OH at active center favorable for acidic OER catalysis; while, with the potential increasing, the net current density was lower than the counterpart of RuO₂ (Fig. S9 in Supporting information) due to the weakened *OH binding strength facilitating its conversion. Besides, the nucleophilic attacked by H₂O is involved in acidic OER catalysis; therefore, methanol oxidation reaction (MOR) is a competitive reaction. With the increment in potential, the current density gap was narrowed for RuO₂/V₂O₅ illustrated the active sites were inconspicuously affected by methanol; while, the RuO₂ was significantly affected by methanol demonstrating H₂O was more susceptible to electrochemically adsorb on active center of RuO₂/V₂O₅. As well known that the acidic OER is a dehydrogenation process; thus, the OER performance was tested under various pH (Fig. S10 in Supporting information). As shown in Fig. 3f, the plot of the current density vs. pH indicated that the reaction order was 8.27 for RuO₂/V₂O₅, which was higher than commercial RuO₂ (5.02) demonstrating the OER performance of RuO₂/V₂O₅ relied on the hydrogen concentration [31]. It was known that the deprotonation is customarily depended on the adjacent atoms. Due to the formation of heterostructure, Ru-O_bri-V structure was detected in RuO₂/V₂O₅ and the unbalanced electron density caused by different electronegativity of Ru (2.20) and V (1.63) led to high hydrogen binding capability for O_bri site. A lower deprotonation capability was observed for commercial RuO₂ due to the electronic symmetry of Ru-O_bri-Ru structure. Thereby, a superior acidic OER performance was observed for RuO₂/V₂O₅ [32].

  Figure 3

  

  Figure 3.  OER performance (a), Tafel slope (b), activation energy (c) and double layer capacitance (d) for RuO₂/V₂O₅, RuO₂–450 and commercial RuO₂. (e) OER activity of RuO₂/V₂O₅ with and without methanol. (f) Plot of pH vs. log∣j (mA/cm²)∣ of RuO₂/V₂O₅, RuO₂–450 and commercial RuO₂.

  DownLoad: Full-Size Img PowerPoint

  As shown in Fig. 4a, the overpotentials at 10 mA/cm² and 50 mA/cm² were 221 mV and 307 mV for RuO₂/V₂O₅ after 1000 cycles, which was similar to its initial performance implying the superb stability. To deeply understand the stability, C_dl was calculated to 33.23 mF/cm² after 1000 cycles (Fig. S11 in Supporting information); moreover, R_ct was 68.1 Ω (Fig. S12 in Supporting information), which was only increased by 1.8%. Thus, it was concluded that the superior stability of RuO₂/V₂O₅ originated from the high structural stability. The HR-TEM image shown in Fig. S13 (Supporting information) suggested the superior structural stability of RuO₂/V₂O₅ stemming from the strong electronic interaction between RuO₂ and V₂O₅. However, as shown in Fig. S14 (Supporting information), commercial RuO₂ showed an inferior stability during 1000 cycles ascribed to the electrochemical decomposition reflected by decrement in C_dl (Fig. S15 in Supporting information). Also, as shown in Fig. 4b, RuO₂/V₂O₅ showed a stable current density within 100 h; in contrast, the OER activity of the commercial RuO₂ was decayed by 74% after merely 2 h. The voltage was also seriously increased for RuO₂–450, indicating the importance of heterostructure for enhancing stability. The OER performance RuO₂/V₂O₅ was well maintained after stability test underscoring the superior stability (Fig. S16 in Supporting information). To certificate the high compositional stability, the cyclic voltammetry curve was recorded. As shown in Fig. 4c, the obvious redox peak was observed for RuO₂/V₂O₅, signal of Ru³⁺/Ru⁴⁺ conversion [33]. It was found that the reversibility was better than commercial RuO₂ because the potential was 0.08 V for RuO₂/V₂O₅, lower than RuO₂ (0.12 V). Thus, the structural stability is higher for RuO₂/V₂O₅. Also, the in-situ electrochemical impedance spectroscopy was carried out. As shown in Fig. 4d, with the same change in applied potential, a larger deviation in phase angle was found for RuO₂/V₂O₅ below 100 Hz than commercial RuO₂ (Fig. 4e) and RuO₂–450 (Fig. S17 in Supporting information) suggesting a better OER performance. Moreover, the R_ct of RuO₂/V₂O₅ was also lower than the counterparts of RuO₂–450 and commercial RuO₂ (Fig. S18 in Supporting information) [34]. It was important to identify the OER mechanism since lattice oxygen mechanism (LOM) and adsorption evolution mechanism (AEM) occur during OER process [35,36]. O₂⁻ and O₂²⁻ are the important reaction intermediates for AEM and LOM; moreover, tetramethylammonium cations are easily to coordinate with O₂²⁻ triggering a serious deterioration in OER performance [37]. As shown in Fig. 4f, the OER catalytic activity was almost stable with TMA⁺ implying RuO₂/V₂O₅ followed AEM pathway. The OER performance was inconspicuously decayed with additional TMA⁺ suggesting the AEM occurred on commercial RuO₂ (Fig. S19 in Supporting information).

  Figure 4

  

  Figure 4.  (a) Cyclic stability of RuO₂/V₂O₅. Stability test (b), cyclic voltammetry curves (c) and bode plots (d, e) of commercial RuO₂ and RuO₂/V₂O₅. (f) OER performance of RuO₂/V₂O₅ with and without TMA⁺.

  DownLoad: Full-Size Img PowerPoint

  As shown in Fig. 5a, the charge density of RuO₂/V₂O₅ suggested the electronic interplay between RuO₂ and V₂O₅; moreover, it was noticed that electric density of Ru atom was decreased; in contrast, an increment in electronic density was detected for V atom at heterointerface, in accordance to XPS analysis. Consequently, the density of state (DOS) of RuO₂/V₂O₅ and RuO₂ was analyzed (Fig. 5b). The d band center of Ru was −1.19 eV and −1.91 eV for RuO₂ and RuO₂/V₂O₅, respectively. The downshifted d band center suggested a lower binding strength with reaction intermediates, which was also reflected by the increment in e_g filling of RuO₂/V₂O₅ shown in Fig. 5c, well matched with methanol detection [38,39]. The d band composes of e_g and t_2g orbitals and e_g occupies the high energy state, which hybridizes with the reaction intermediates; therefore, the e_g filling is vital for predicting the binding strength between active site and reaction coordinates. As shown in Fig. S12 (Supporting information), the free energy for various reaction intermediates was calculated based on AEM mechanism. As listed in Fig. 5d, the free energy for rate limiting step, formation of *OOH moiety, was 2.06 eV and 2.43 eV for RuO₂/V₂O₅ and RuO₂, respectively. Theoretical calculation indicated that RuO₂/V₂O₅ performed a better OER performance with relative to RuO₂.

  Figure 5

  

  Figure 5.  (a) Charge density of RuO₂/V₂O₅. Density of state (b), e_g filling (c) and OER energy barrier (d) of RuO₂ and RuO₂/V₂O₅.

  DownLoad: Full-Size Img PowerPoint

  In this work, we have synthesized RuO₂/V₂O₅ heterostructured nanoneedle using MIL-88B as template. The formed RuO₂/V₂O₅ performed a better acidic OER activity than commercial IrO₂, demanding 216 mV and 243 mV overpotential to reach 10 mA/cm², corresponding to a 6-time higher mass activity. From the pH-independent test a higher deprotonation capability was recorded for RuO₂/V₂O₅ contributing to a boosted OER performance. Also, the cyclic voltammetry curve illustrated that the oxidation potential for the formation of Ru⁴⁺ was increased for RuO₂/V₂O₅ leading to a superior resistance towards electrochemical oxidation; as a result, a robust stability was achieved for RuO₂/V₂O₅. The DFT calculation indicated the introduction of V₂O₅ to RuO₂ downshifted d band center and increased the e_g filling of Ru resulting in a lower energy barrier for the formation of *OOH species.

  Declaration of competing interest

  The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

  CRediT authorship contribution statement

  Qing Li: Data curation. Yumei Feng: Data curation. Yuhua Xie: Data curation. Qi Xu: Data curation. Yifei Li: Data curation. Yingjie Yu: Data curation. Fang Luo: Supervision, Resources, Funding acquisition. Zehui Yang: Writing – review & editing, Writing – original draft, Supervision.

  Acknowledgments

  This work is supported by the National Natural Science Foundation of China (No. 22209126) and the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, Jianghan University (No. JDGD-202314). The authors also thank Dr. Liu from the Analytical and Testing Center of Wuhan Textile University for her assistance with XPS test and helpful analysis.

  Supplementary materials

  Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.cclet.2025.111074.

  
  
• 1. [1]

     X. Li, W. Xu, Y. Fang, et al., SusMat 3 (2023) 160–179. doi: 10.1002/sus2.114

  2. [2]

     Y. Feng, Y. Xie, Y. Yu, et al., Angew. Chem. Int. Ed. 64 (2025) e202413417.

  3. [3]

     Y. Hao, S.F. Hung, L. Wang, et al., Nat. Commun. 15 (2024) 8015.

  4. [4]

     Y. Hao, S.F. Hung, W.J. Zeng, et al., J. Am. Chem. Soc. 145 (2023) 23659–23669. doi: 10.1021/jacs.3c07777

  5. [5]

     L. Deng, S.F. Hung, S. Liu, et al., J. Am. Chem. Soc. 146 (2024) 23146–23157. doi: 10.1021/jacs.4c05070

  6. [6]

     Q. Li, Y. Feng, Y. Yu, et al., Chin. Chem. Lett. 36 (2025) 110612.

  7. [7]

     J. Ying, J.B. Chen, Y.X. Xiao, et al., J. Mater. Chem. A 11 (2023) 1634–1650. doi: 10.1039/d2ta07196g

  8. [8]

     M. Kim, J. Park, M. Wang, et al., Appl. Catal. B 302 (2022) 120834.

  9. [9]

     Y. Xie, Y. Feng, S. Pan, et al., Adv. Funct. Mater. 34 (2024) 2406351.

  10. [10]

      Z. Chen, N. Han, W. Wei, et al., EcoEnergy 2 (2024) 114–140.

  11. [11]

      J. Ge, X. Wang, H. Tian, et al., Chin. Chem. Lett. 35 (2025) 109906.

  12. [12]

      N. Yao, H. Jia, J. Zhu, et al., Chem 9 (2023) 1882–1896.

  13. [13]

      W. Zhu, K. Yin, M. Ma, et al., Chin. Chem. Lett. (2024), doi: 10.1016/j.cclet.2024.110749.

  14. [14]

      Q. Wu, R. Zhou, Z. Yao, et al., Chin. Chem. Lett. 35 (2024) 109416.

  15. [15]

      H. Song, X. Yong, G.I.N. Waterhouse, et al., ACS Catal. 14 (2024) 3298–3307. doi: 10.1021/acscatal.3c06182

  16. [16]

      Y. Wu, R. Yao, K. Zhang, et al., Chem. Eng. J. 479 (2024) 147939.

  17. [17]

      W. Zhu, X. Song, F. Liao, et al., Nat. Commun. 14 (2023) 5365.

  18. [18]

      J. Zhu, Y. Guo, F. Liu, et al., Angew. Chem. Int. Ed. 60 (2021) 12328–12334. doi: 10.1002/anie.202101539

  19. [19]

      D. Zhang, M. Li, X. Yong, et al., Nat. Commun. 14 (2023) 2517.

  20. [20]

      Y. Wang, K. Wei, Y. Song, et al., Chem. Eng. J. 497 (2024) 154724.

  21. [21]

      J. Wang, C. Cheng, Q. Yuan, et al., Chem 8 (2022) 1673–1687.

  22. [22]

      C. Hao, H. Lv, Q. Zhao, et al., Int. J. Hydrogen Energy 42 (2017) 9384–9395.

  23. [23]

      Y. Cheng, Y. Wang, Z. Shi, et al., EcoEnergy 3 (2025) 131–155. doi: 10.1002/ece2.79

  24. [24]

      L. Liu, Y. Ji, W. You, et al., Small 19 (2023) 2208202.

  25. [25]

      S. Li, G. Xing, S. Zhao, et al., Natl. Sci. Rev. 11 (2024) nwae193.

  26. [26]

      S. Zhao, S.F. Hung, L. Deng, et al., Nat. Commun. 15 (2024) 2728.

  27. [27]

      Y. Wang, R. Yang, Y. Ding, et al., Nat. Commun. 14 (2023) 1412. doi: 10.3390/cryst13101412

  28. [28]

      C. Liu, B. Sheng, Q. Zhou, et al., Nano Res. 15 (2022) 7008–7015. doi: 10.1007/s12274-022-4337-z

  29. [29]

      T. Xiong, X. Li, Z. Ma, et al., J. Colloid Interface Sci. 672 (2024) 170–178.

  30. [30]

      S. Xin, Y. Tang, B. Jia, et al., Adv. Funct. Mater. 33 (2023) 2305243.

  31. [31]

      H. Jia, N. Yao, Z. Liao, et al., Angew. Chem. Int. Ed. 63 (2024) e202408005.

  32. [32]

      S. Chen, S. Zhang, L. Guo, et al., Nat. Commun. 14 (2023) 4127.

  33. [33]

      Z. Shi, J. Li, Y. Wang, et al., Nat. Commun. 14 (2023) 843.

  34. [34]

      H. Su, W. Zhou, W. Zhou, et al., Nat. Commun. 12 (2021) 6118.

  35. [35]

      X. Wang, S. Xi, P. Huang, et al., Nature 611 (2022) 702–708. doi: 10.1038/s41586-022-05296-7

  36. [36]

      Z. Wu, Y. Wang, D. Liu, et al., Adv. Funct. Mater. 33 (2023) 2307010.

  37. [37]

      Z. Feng, C. Dai, P. Shi, et al., Chem. Eng. J. 485 (2024) 149992.

  38. [38]

      H. Jia, N. Yao, Y. Jin, et al., Nat. Commun. 15 (2024) 5419.

  39. [39]

      Y. Xie, Y. Feng, S. Zhu, et al., Adv. Mater. 37 (2025) 2414801.

• 

  Figure 1  (a) XRD patterns of RuO₂/V₂O₅, RuO₂–450 and V₂O₅. (b) Ru 3p XPS spectra of RuO₂/V₂O₅ and RuO₂–450. (c) V 2p_3/2 XPS spectra of V₂O₅ and RuO₂/V₂O₅. (d) O 1s XPS spectra of RuO₂–450, RuO₂/V₂O₅ and V₂O₅.

  下载: 全尺寸图片 幻灯片
  

  Figure 2  SEM (a), TEM (b), HR-TEM (c), HAADF-STEM (d) and relative EDS mapping of RuO₂/V₂O₅.

  下载: 全尺寸图片 幻灯片
  

  Figure 3  OER performance (a), Tafel slope (b), activation energy (c) and double layer capacitance (d) for RuO₂/V₂O₅, RuO₂–450 and commercial RuO₂. (e) OER activity of RuO₂/V₂O₅ with and without methanol. (f) Plot of pH vs. log∣j (mA/cm²)∣ of RuO₂/V₂O₅, RuO₂–450 and commercial RuO₂.

  下载: 全尺寸图片 幻灯片
  

  Figure 4  (a) Cyclic stability of RuO₂/V₂O₅. Stability test (b), cyclic voltammetry curves (c) and bode plots (d, e) of commercial RuO₂ and RuO₂/V₂O₅. (f) OER performance of RuO₂/V₂O₅ with and without TMA⁺.

  下载: 全尺寸图片 幻灯片
  

  Figure 5  (a) Charge density of RuO₂/V₂O₅. Density of state (b), e_g filling (c) and OER energy barrier (d) of RuO₂ and RuO₂/V₂O₅.

  下载: 全尺寸图片 幻灯片
•