在这项工作中,进行了密度泛函理论(DFT)计算以研究一系列过渡金属(Cr,Mn,Fe,Co,Ni,Cu,Zn,Zr,Nb,Ru,Rh,Pd,Ag,Hf,Ta,Os,Ir,和Pt)作为单原子组分引入Ti-BPDC(BPDC=2,2'-联吡啶-5,5'-二羧酸)作为催化剂(M/Ti-BPDC)用于光催化还原CO2。结果表明,Fe/Ti-BPDC由于其较小的极限电位(-0.40V),是将CO2还原为HCOOH的最活跃候选物。Ag,Cr,Mn,Ru,Zr,Nb,Rh,和Cu改性的Ti-BPDC对HCOOH也有活性,因为它们的极限电势适中,尽管这些材料的反应机理不同。大多数研究的催化剂对CO产物的活性和选择性差,因为*COOH/*OCOH中间体的稳定性明显弱于*OCHO/*HCOO物质。*CO在Pd/Ti-BPDC上的中等结合强度是其对CH3OH生成的优异催化活性的原因。进行电子结构分析以揭示在M/Ti-BPDC上将CO2还原为不同产物的活性趋势的起源。计算结果表明,设计单原子金属基MOF催化剂可以有效地调节CO2光还原的活性和选择性。
In this work, density functional theory (DFT) calculations were conducted to investigate a series of transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Rh, Pd, Ag, Hf, Ta, Os, Ir, and Pt) as single-atom components introduced into Ti-BPDC (BPDC=2,2\'-bipyridine-5,5\'-dicarboxylic acid) as catalysts (M/Ti-BPDC) for the photocatalytic reduction of CO2. The results show that Fe/Ti-BPDC is the most active candidate for CO2 reduction to HCOOH due to its small limiting potential (-0.40 V). Ag, Cr, Mn, Ru, Zr, Nb, Rh, and Cu modified Ti-BPDC are also active to HCOOH since their limiting potentials are moderate although the reaction mechanisms are different across these materials. Most of the studied catalysts show poor activity and selectivity to CO product because the stability of *COOH/*OCOH intermediates is significantly weaker than *OCHO/*HCOO species. The moderate binding strength of *CO on Pd/Ti-BPDC is responsible for its superior catalytic activity toward CH3OH generation. Electronic structural analysis was performed to uncover the origin of the activity trend for CO2 reduction to different products on M/Ti-BPDC. The calculation results indicate that the activity and selectivity of CO2 photoreduction can be effectively tuned by designing single-atom metal-based MOF catalysts.