Ni(NH_(3))_(6)^(2+) more efficient than Ni(H_(2)O)_(6)^(2+) and Ni(OH)_(2) for catalyzing water and phenol oxidation on illuminated Bi_(2)MoO_(6) with visible light

作     者：Yaru Wang Yechen Wang Xubo Huang Min Chen Yiming Xu Yaru Wang;Yechen Wang;Xubo Huang;Min Chen;Yiming Xu

作者机构：State Key Laboratory of Silicon Materials and Department of ChemistryZhejiang UniversityHangzhou 310027China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2023年第126卷第4期

页      面：556-564页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 0703[理学-化学] 

基　　金：supported by the Funds for Creative Research Group of NSFC (No.21621005)。 

主　　题：Semiconductor Photocatalysis Organic degradation Water oxidation Bismuth molybdate Nickel hexammine perchlorate 

摘      要：Nickel (hydr)oxide (NiOH) is known to be good co-catalyst for the photoelectrochemical oxidation of water,and for the photocatalytic oxidation of organics on different semiconductors.Herein we report a greatly improved activity of Bi_(2)MoO_(6)(BMO) by nickel hexammine perchlorate (NiNH).Under visible light,phenol oxidation on BMO was slow.After NiNH,NiOH,and Ni^(2+)loading,a maximum rate of phenol oxidation increased by factors of approximately 16,8.8,and 4.7,respectively.With a BMO electrode,all catalysts inhibited O_(2)reduction,enhanced water (photo-)oxidation,and facilitated the charge transfer at solidliquid interface,respectively,the degree of which was always NiNHNiOHNi^(2+).Solid emission spectra indicated that all catalysts improved the charge separation of BMO,the degree of which also varied as NiNHNiOHNi^(2+).Furthermore,after a phenol-free aqueous suspension of NiNH/BMO was irradiated,there was a considerable Ni(Ⅲ) species,but a negligible NH_(2)radical.Accordingly,a plausible mechanism is proposed,involving the hole oxidation of Ni(Ⅱ) into Ni(Ⅳ),which is reactive to phenol oxidation,and hence promotes O_(2)reduction.Because NH_(3)is a stronger ligand than H_(2)O,the Ni(Ⅱ) oxidation is easier for Ni(NH_(3))6+than for Ni(H_(2)O)6+.This work shows a simple route how to improve BMO photocatalysis through a co-catalyst.