Self-supporting and hierarchically porous Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure as a bifunctional electrocatalyst for fluctuating overall water splitting  

作　　者：Wenjing Yan Jintao Zhang Aijing Lü Songle Lu Yiwei Zhong Mingyong Wang 

机构地区：[1]State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China [2]Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2022年第5期1120-1131,共12页矿物冶金与材料学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 51874020 and 52004022)

摘　　要：Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure as bifunctional electrocatalyst was constructed based on porous Ni-Fe electrodeposition on three-dimensional(3D)carbon fiber cloth,in situ oxidation,and chemical sulfuration.Results showed that the Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure with a large specific surface area exhibits good bifunctional activity and stability for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)because of the abundance of active sites,synergistic effect of the heterostructure,superhydrophilic surface,and stable,self-supporting structure.The results further confirmed that the Ni_(x)Fe-S phase in the heterostructure is transformed into metal oxides/hydroxides and Ni_(3)S_(2) during OER.Compared with the commercial 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer,the self-supporting Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) electrolyzer exhibits better stability and lower cell voltage in the fluctu-ating current density range of 10-500 mA/cm^(2).Particularly,the cell voltage of Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) is only approximately 3.91 V at an industrial current density of 500 mA/cm^(2),which is lower than that of the 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer(i.e.,approximately 4.79 V).This work provides a promising strategy to develop excellent bifunctional electrocatalysts for fluctuating overall water splitting.

关 键 词：SELF-SUPPORTING hierarchically porous structure HETEROSTRUCTURE bifunctional catalyst overall water splitting 

分 类 号：TQ116.2[化学工程—无机化工] TQ426