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2023 Volume 42 Issue 8
2023, 42(8): 100088
doi: 10.1016/j.cjsc.2023.100088
Abstract:
The creation of anodic ethanol oxidation reaction catalysts with superior all-around performance for direct ethanol fuel cells (DEFCs) has continued to attract the attention of researchers. An ultrathin trimetallic PtAuBi aerogel with branching, rough-surfaced 1D nanowires that self-assemble into a 3D porous network structure has been created in this study. It has a mass activity (MA) of 8045 mA mgPt-1 in an alkaline medium, which is 7.56 times greater than that of commercial Pt/C (1064 mA mgPt-1). Notably, the catalytic activity and resistance to CO poisoning of PtAuBi aerogels were improved by the addition of an efficient "active additive" Au. The results analysis reveals that the increased performance of PtAuBi aerogel is mostly attributable to the integrated function of the 3D porous network structure, the downward shift of the Pt d-band center, and the synergistic effect of the "Pt- Bi" and/or "Pt- Au" dual active sites.
The creation of anodic ethanol oxidation reaction catalysts with superior all-around performance for direct ethanol fuel cells (DEFCs) has continued to attract the attention of researchers. An ultrathin trimetallic PtAuBi aerogel with branching, rough-surfaced 1D nanowires that self-assemble into a 3D porous network structure has been created in this study. It has a mass activity (MA) of 8045 mA mgPt-1 in an alkaline medium, which is 7.56 times greater than that of commercial Pt/C (1064 mA mgPt-1). Notably, the catalytic activity and resistance to CO poisoning of PtAuBi aerogels were improved by the addition of an efficient "active additive" Au. The results analysis reveals that the increased performance of PtAuBi aerogel is mostly attributable to the integrated function of the 3D porous network structure, the downward shift of the Pt d-band center, and the synergistic effect of the "Pt- Bi" and/or "Pt- Au" dual active sites.
2023, 42(8): 100095
doi: 10.1016/j.cjsc.2023.100095
Abstract:
Bismuth (Bi)-based nanomaterials are highly efficient electrocatalysts for carbon dioxide reduction (CO2RR), which still have huge scope for synthesis optimization and performance improvement. In this work, we develop a fast ultrasound-assisted galvani replacement reaction to synthesize two-dimensional metallic Bi metallene (Bi ML) with an ultrathin thickness of 1.5 nm, high surface area, and abundant atomic defects. The electrochemical characterization shows that Bi ML can achieve a faradaic efficiency of ~94% for the CO2RR to formate, accompanied by good stability. Density functional theory calculations show that the atomic vacancy can change the electronic structure of the surrounding atoms, which contributes to the selectivity enhancement of the CO2RR for formate production. This work provides an efficient method for the rapid large-scale preparation of high-performance Bibased two-dimensional nanomaterials for the CO2RR.
Bismuth (Bi)-based nanomaterials are highly efficient electrocatalysts for carbon dioxide reduction (CO2RR), which still have huge scope for synthesis optimization and performance improvement. In this work, we develop a fast ultrasound-assisted galvani replacement reaction to synthesize two-dimensional metallic Bi metallene (Bi ML) with an ultrathin thickness of 1.5 nm, high surface area, and abundant atomic defects. The electrochemical characterization shows that Bi ML can achieve a faradaic efficiency of ~94% for the CO2RR to formate, accompanied by good stability. Density functional theory calculations show that the atomic vacancy can change the electronic structure of the surrounding atoms, which contributes to the selectivity enhancement of the CO2RR for formate production. This work provides an efficient method for the rapid large-scale preparation of high-performance Bibased two-dimensional nanomaterials for the CO2RR.
2023, 42(8): 100103
doi: 10.1016/j.cjsc.2023.100103
Abstract:
DFT calculations have been performed to explore the defective structures and oxidation properties of Janus AsP. By comparing the structural stabilities of these defective structures, the SW-I possesses the smallest formation energy of only 0.103 eV, which is easy to form on the Janus AsP surface, while DV-555777 defects have relatively high formation energies due to the larger structural distortion. The SV defects induce the electronic defect states near the Fermi level, but SW and DVs defects do not. Different from BP, where the O2 molecule will dissociate spontaneously on its surface, the dissociation of O2 molecule on Janus AsP needs to overcome a large barrier, i.e., 0.98 eV for SW-I and 0.93 eV for SV-5566-I. Our work has indicated that the Janus AsP possesses better oxidation resistance than BP, and even with surface defects, they provide wide applications in electronic and optical devices.
DFT calculations have been performed to explore the defective structures and oxidation properties of Janus AsP. By comparing the structural stabilities of these defective structures, the SW-I possesses the smallest formation energy of only 0.103 eV, which is easy to form on the Janus AsP surface, while DV-555777 defects have relatively high formation energies due to the larger structural distortion. The SV defects induce the electronic defect states near the Fermi level, but SW and DVs defects do not. Different from BP, where the O2 molecule will dissociate spontaneously on its surface, the dissociation of O2 molecule on Janus AsP needs to overcome a large barrier, i.e., 0.98 eV for SW-I and 0.93 eV for SV-5566-I. Our work has indicated that the Janus AsP possesses better oxidation resistance than BP, and even with surface defects, they provide wide applications in electronic and optical devices.
2023, 42(8): 100105
doi: 10.1016/j.cjsc.2023.100105
Abstract:
In the active Mn4CaO5 cluster of the natural water oxidation system, one of the dangling Mn atom is surrounded by water molecules through coordination and hydrogen bonding. It means that the enrichment of water molecules around the Mn catalysts has a positive effect on the water oxidation catalysis. Inspired by nature photosynthesis, the hydrophilic surfaces are believed to be able to capture water molecules to assist water oxidation. Herein, we report MnO2@PFANI nanowires with improved mass transfer efficiency and conductivity for electrocatalytic water oxidation. The as-prepared nanowires are synthesized by coating hydrophilic polymers on MnO2 nanowires. The hydrophilic surface captures water molecule and promote mass transfer processes, and the conductivity of the polymer can also increase charge transfer processes. To reach a current density of 10 mA cm-2, a low overpotential of 440 mV is required in a 1.0 M KOH solution for the MnO2@PFANI nanowires. The hydrophilicity and conductivity are systematically investigated by both physical and electrochemical measurements. This study provides a surface engineering idea for the fabrication of efficient electrocatalysts.
In the active Mn4CaO5 cluster of the natural water oxidation system, one of the dangling Mn atom is surrounded by water molecules through coordination and hydrogen bonding. It means that the enrichment of water molecules around the Mn catalysts has a positive effect on the water oxidation catalysis. Inspired by nature photosynthesis, the hydrophilic surfaces are believed to be able to capture water molecules to assist water oxidation. Herein, we report MnO2@PFANI nanowires with improved mass transfer efficiency and conductivity for electrocatalytic water oxidation. The as-prepared nanowires are synthesized by coating hydrophilic polymers on MnO2 nanowires. The hydrophilic surface captures water molecule and promote mass transfer processes, and the conductivity of the polymer can also increase charge transfer processes. To reach a current density of 10 mA cm-2, a low overpotential of 440 mV is required in a 1.0 M KOH solution for the MnO2@PFANI nanowires. The hydrophilicity and conductivity are systematically investigated by both physical and electrochemical measurements. This study provides a surface engineering idea for the fabrication of efficient electrocatalysts.
2023, 42(8): 100107
doi: 10.1016/j.cjsc.2023.100107
Abstract:
Chiral metal surfaces of CO2 electro-reduction catalysts could significantly influence CO2 reduction product species, even able to product amino acids. On the other hand, CISS effects have been started to be applicated in electrocatalysts, which significantly enhances the catalytic activity on OER. Thus, it is a promising future for CO2 electro-reduction that employs chiral materials with both chiral surface and CISS effects to enhance the catalytic activity of catalysts. In order to achieve this goal, the most critical issue to be addressed is the synthesis of copper materials with highly oriented and ordered chiral helical structures.
Chiral metal surfaces of CO2 electro-reduction catalysts could significantly influence CO2 reduction product species, even able to product amino acids. On the other hand, CISS effects have been started to be applicated in electrocatalysts, which significantly enhances the catalytic activity on OER. Thus, it is a promising future for CO2 electro-reduction that employs chiral materials with both chiral surface and CISS effects to enhance the catalytic activity of catalysts. In order to achieve this goal, the most critical issue to be addressed is the synthesis of copper materials with highly oriented and ordered chiral helical structures.
2023, 42(8): 100117
doi: 10.1016/j.cjsc.2023.100117
Abstract:
2023, 42(8): 100143
doi: 10.1016/j.cjsc.2023.100143
Abstract:
2023, 42(8): 100145
doi: 10.1016/j.cjsc.2023.100145
Abstract:
Ternary sulfide solid solutions have garnered great attention in photocatalytic water splitting due to their tunable electronic property, low cost, and sufficient light-absorption performance. Herein, a series of MnxCd1-xS samples with different Mn/Cd molar ratios were synthesized by solvothermal method and used for photocatalytic hydrogen production under visible light. The Mn0.2Cd0.8S and Mn0.4Cd0.6S were demonstrated to be the solid solutions, while Mn0.6Cd0.4S and Mn0.8Cd0.2S consist of MnxCd1−xS solid solution and MnS. In addition, the Mn0.4Cd0.6S exhibited the highest photocatalytic performance with the H2 production rate of 185.95 μmol·h-1, which was 4.7 times higher than that of CdS. Without the cocatalyst, the quantum efficiency of Mn0.4Cd0.6S reached 2.04% at 400 nm. In addition, the Mn0.4Cd0.6S solid solution also showed high stability during the photocatalytic H2 production reaction. The effect of the Mn/Cd molar ratio on the microstructure, band gap structure, and photocatalytic hydrogen production performance of MnxCd1−xS was revealed systematically. The excellent photocatalytic H2 production performance of the Mn0.4Cd0.6S solid solution is mainly due to its enhanced reducing potential and high charge separation efficiency.
Ternary sulfide solid solutions have garnered great attention in photocatalytic water splitting due to their tunable electronic property, low cost, and sufficient light-absorption performance. Herein, a series of MnxCd1-xS samples with different Mn/Cd molar ratios were synthesized by solvothermal method and used for photocatalytic hydrogen production under visible light. The Mn0.2Cd0.8S and Mn0.4Cd0.6S were demonstrated to be the solid solutions, while Mn0.6Cd0.4S and Mn0.8Cd0.2S consist of MnxCd1−xS solid solution and MnS. In addition, the Mn0.4Cd0.6S exhibited the highest photocatalytic performance with the H2 production rate of 185.95 μmol·h-1, which was 4.7 times higher than that of CdS. Without the cocatalyst, the quantum efficiency of Mn0.4Cd0.6S reached 2.04% at 400 nm. In addition, the Mn0.4Cd0.6S solid solution also showed high stability during the photocatalytic H2 production reaction. The effect of the Mn/Cd molar ratio on the microstructure, band gap structure, and photocatalytic hydrogen production performance of MnxCd1−xS was revealed systematically. The excellent photocatalytic H2 production performance of the Mn0.4Cd0.6S solid solution is mainly due to its enhanced reducing potential and high charge separation efficiency.
