Electrochemical water splitting produces“green hydrogen,”a clean,sustainable fuel that can eventually contribute to carbon neutrality.However,the big challenge to the widespread adoption of water-splitting technolog...Electrochemical water splitting produces“green hydrogen,”a clean,sustainable fuel that can eventually contribute to carbon neutrality.However,the big challenge to the widespread adoption of water-splitting technology is the complex synthesis routes that involve harmful or expensive chemicals and sluggish reaction kinetics.This work presents a scalable and environmentally friendly solvent-free strategy for in situ synthesis of highly dispersed CeO_(2)/CoFe nanoparticles encapsulated within 3D hierarchically porous carbon heterostructures(CeO_(2)/CoFe@C)via a simple pyrolysis process.The optimized Ce_(20)/CoFe@C/750 catalyst shows low overpotentials of 114 and 191 mV at 10 mA cm^(−2)toward the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER),respectively,in 1.0 M KOH.Two-electrode systems achieve a cell voltage of 1.508@10 mA cm^(−2)with robust stability over 500 h in 1.0 M KOH.This notable performance is attributed to the hierarchically porous nanosheet architecture with a superhydrophilic surface that facilitates mass transport,and rapid H_(2)/O_(2)gas bubble escape,and the synergistically coupled CeO_(2)/CoFe heterointerface and abundant oxygen vacancies boost overall activity,particularly for the OER.Additionally,experimental results indicate that the optimum performance depends critically on the effect of changing Ce concentration.Density functional theory(DFT)calculations suggest that optimizing the CeO_(2)/CoFe interface triggered CeO_(2)reconstruction,where oxygen migration to CoFe created vacancies.Also,this reduction of the Ce site at the interface and the availability of d and f orbitals contribute to bonding and antibonding adsorbates,thereby moderating their adsorption energy and boosting OER activity.This study demonstrates the significance of rational design concepts in catalyst structure optimization,resulting in noticeably improved overall water-splitting performance.展开更多
The development of porous metal phosphides with abundant active sites is of great importance for efficient electrocatalytic water splitting.In this work,three-dimensional(3D)-ordered mesoporous irondoped cobalt phosph...The development of porous metal phosphides with abundant active sites is of great importance for efficient electrocatalytic water splitting.In this work,three-dimensional(3D)-ordered mesoporous irondoped cobalt phosphide(meso-Co_(2-x)Fe_(x)P)was prepared by a nanocasting strategy using SBA-15 as the hard template combined with a subsequent phosphidation.The unique mesoporous structure of the meso-Co_(2-x)Fe_(x)P electrocatalyst resulted in the exposure of abundant active sites and favorable mass transfer for the electrocatalytic process.Due to the synergy effects of the mesoporous structure and ternary component,the meso-Co_(2-x)Fe_(x)P exhibited outstanding electrocatalytic activity with low overpotentials of 93.7 mV and 266.4 mV at a current density of 10 mA cm^(-2) for HER and OER,respectively.In addition,meso-Co_(2-x)Fe_(x)P showed excellent overall water splitting activity with an external voltage of 1.58 V at a current density of 10 mA cm^(-2),superior to the electrolytic cell consisting of 20%Pt/C and RuO_(2),demonstrating it has great potential for practical application in overall water splitting.展开更多
基金financially supported by the National Natural Science Foundation of China(W2433031 and 22350410392)Fundamental Research and Development Plan of Zhenjiang City in 2024(Industry Foresight and Common Key Technologies GY2024027 and GJ2024012).
文摘Electrochemical water splitting produces“green hydrogen,”a clean,sustainable fuel that can eventually contribute to carbon neutrality.However,the big challenge to the widespread adoption of water-splitting technology is the complex synthesis routes that involve harmful or expensive chemicals and sluggish reaction kinetics.This work presents a scalable and environmentally friendly solvent-free strategy for in situ synthesis of highly dispersed CeO_(2)/CoFe nanoparticles encapsulated within 3D hierarchically porous carbon heterostructures(CeO_(2)/CoFe@C)via a simple pyrolysis process.The optimized Ce_(20)/CoFe@C/750 catalyst shows low overpotentials of 114 and 191 mV at 10 mA cm^(−2)toward the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER),respectively,in 1.0 M KOH.Two-electrode systems achieve a cell voltage of 1.508@10 mA cm^(−2)with robust stability over 500 h in 1.0 M KOH.This notable performance is attributed to the hierarchically porous nanosheet architecture with a superhydrophilic surface that facilitates mass transport,and rapid H_(2)/O_(2)gas bubble escape,and the synergistically coupled CeO_(2)/CoFe heterointerface and abundant oxygen vacancies boost overall activity,particularly for the OER.Additionally,experimental results indicate that the optimum performance depends critically on the effect of changing Ce concentration.Density functional theory(DFT)calculations suggest that optimizing the CeO_(2)/CoFe interface triggered CeO_(2)reconstruction,where oxygen migration to CoFe created vacancies.Also,this reduction of the Ce site at the interface and the availability of d and f orbitals contribute to bonding and antibonding adsorbates,thereby moderating their adsorption energy and boosting OER activity.This study demonstrates the significance of rational design concepts in catalyst structure optimization,resulting in noticeably improved overall water-splitting performance.
基金supported by National Natural Science Foundation of China(21878130)China Postdoctoral Science Foundation(2018M642180 and 2017T110453).
文摘The development of porous metal phosphides with abundant active sites is of great importance for efficient electrocatalytic water splitting.In this work,three-dimensional(3D)-ordered mesoporous irondoped cobalt phosphide(meso-Co_(2-x)Fe_(x)P)was prepared by a nanocasting strategy using SBA-15 as the hard template combined with a subsequent phosphidation.The unique mesoporous structure of the meso-Co_(2-x)Fe_(x)P electrocatalyst resulted in the exposure of abundant active sites and favorable mass transfer for the electrocatalytic process.Due to the synergy effects of the mesoporous structure and ternary component,the meso-Co_(2-x)Fe_(x)P exhibited outstanding electrocatalytic activity with low overpotentials of 93.7 mV and 266.4 mV at a current density of 10 mA cm^(-2) for HER and OER,respectively.In addition,meso-Co_(2-x)Fe_(x)P showed excellent overall water splitting activity with an external voltage of 1.58 V at a current density of 10 mA cm^(-2),superior to the electrolytic cell consisting of 20%Pt/C and RuO_(2),demonstrating it has great potential for practical application in overall water splitting.
