Guo Zhi-Yan, Li Chen-Xuan, Gao Miao, Han Xiao, Zhang Ying-Jie, Zhang Wen-Jun, Li Wen-Wei
Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, 230026, China.
USTC-CityU Joint Advanced Research Center, Suzhou, 215123, China.
Angew Chem Int Ed Engl. 2021 Jan 4;60(1):274-280. doi: 10.1002/anie.202010828. Epub 2020 Oct 27.
Transition metal (TM)-based bimetallic spinel oxides can efficiently activate peroxymonosulfate (PMS) presumably attributed to enhanced electron transfer between TMs, but the existing model cannot fully explain the efficient TM redox cycling. Here, we discover a critical role of TM-O covalency in governing the intrinsic catalytic activity of Co Mn O spinel oxides. Experimental and theoretical analysis reveals that the Co sites significantly raises the Mn valence and enlarges Mn-O covalency in octahedral configuration, thereby lowering the charge transfer energy to favor Mn -PMS interaction. With appropriate Mn /Mn ratio to balance PMS adsorption and Mn reduction, the Co Mn O exhibits remarkable catalytic activities for PMS activation and pollutant degradation, outperforming all the reported TM spinel oxides. The improved understandings on the origins of spinel oxides activity for PMS activation may inspire the development of more active and robust metal oxide catalysts.
基于过渡金属（TM）的双金属尖晶石氧化物可以有效地激活过一硫酸盐（PMS），这可能归因于过渡金属之间增强的电子转移，但现有的模型不能完全解释高效的过渡金属氧化还原循环。在这里，我们发现了TM-O共价性在控制CoMn₂O₄尖晶石氧化物的本征催化活性方面的关键作用。实验和理论分析表明，Co位点显著提高了八面体构型中Mn的价态并扩大了Mn-O共价性，从而降低了电荷转移能以促进Mn-PMS相互作用。通过适当的Mn³⁺/Mn²⁺比例来平衡PMS吸附和Mn还原，CoMn₂O₄对PMS活化和污染物降解表现出显著的催化活性，优于所有已报道的过渡金属尖晶石氧化物。对尖晶石氧化物PMS活化活性起源的深入理解可能会激发更具活性和稳定性的金属氧化物催化剂的开发。
