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Bimetal Schottky Heterojunction Boosting Energy‐Saving Hydrogen Production from Alkaline Water via Urea Electrocatalysis
Author(s) -
Wang Chao,
Lu Haoliang,
Mao Zeyang,
Yan Chenglin,
Shen Guozhen,
Wang Xianfu
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202000556
Subject(s) - electrocatalyst , oxygen evolution , materials science , hydrogen production , bimetal , overpotential , water splitting , bifunctional , electrolysis , inorganic chemistry , catalysis , electrolysis of water , chemical engineering , urea , reversible hydrogen electrode , electrode , electrochemistry , chemistry , electrolyte , working electrode , photocatalysis , composite material , organic chemistry , engineering
Hydrogen production via water electrocatalysis is limited by the sluggish anodic oxygen evolution reaction (OER) that requires a high overpotential. In response, a urea‐assisted energy‐saving alkaline hydrogen‐production system has been investigated by replacing OER with a more oxidizable urea oxidation reaction (UOR). A bimetal heterostructure CoMn/CoMn 2 O 4 as a bifunctional catalyst is constructed in an alkaline system for both urea oxidation and hydrogen evolution reaction (HER). Based on the Schottky heterojunction structure, CoMn/CoMn 2 O 4 induces self‐driven charge transfer at the interface, which facilitates the absorption of reactant molecules and the fracture of chemical bonds, therefore triggering the decomposition of water and urea. As a result, the heterostructured electrode exhibits ultralow potentials of −0.069 and 1.32 V (vs reversible hydrogen electrode) to reach 10 mA cm −2 for HER and UOR, respectively, in alkaline solution, and the full urea electrolysis driven by CoMn/CoMn 2 O 4 delivers 10 mA cm −2 at a relatively low potential of 1.51 V and performs stably for more than 15 h. This represents a novel strategy of Mott–Schottky hybrids in electrocatalysts and should inspire the development of sustainable energy conversion by combining hydrogen production and sewage treatment.