依赖于尺寸和载体的Ptn/X-石墨烯催化剂（X = C、B、N）减弱CO中毒

【原文摘要】

  一氧化碳中毒是铂基催化剂应用于电催化过程的主要障碍之一。本文基于DFT+D3 计算，通过B 和N 掺杂石墨 烯并改变团簇尺寸以减弱Pt 催化剂的CO 中毒现象。计算得到了能量上最有利的Ptn/X-石墨烯(X = C, B, N; n = 1‒6, 13)结构，且Ptn 和X-石墨烯之间的结合能依赖于团簇尺寸与载体，顺序为：Ptn/B-g > Ptn/N-g > Ptn/C-g。低 配位及突出的原子作为主要活性位点参与反应。由于d 带中心的位置和界面引起的电子转移，中等大小团簇(n = 4‒6)能有效抑制CO 中毒，具有优异的CO 氧化性能。此外揭示了以第二次CO2 解吸为速控步的E-R 机制主导 的反应路线。Ptn/B-g (n = 4,5,6)对应的活化能垒分别为0.53、0.61 和0.56 eV。这项工作为抗CO 中毒的Ptn/Xg 催化剂在燃料电池中的应用与设计提供了理论指导。

 【图文速览】

Fig. 1 Configurations of Pt clusters adsorption on pristine and B/N-doped graphenes, where gray, green, blue, and dark bluerepresent C, B, N, and Pt, respectively  

Fig. 2 Normalized total DOS and local DOS of Pt13/X-g X = (C,B, N) with an energy scale from –8.0 to 8.0 eV, wherecontribution from B and N around Fermi level (–8.0 to 0 eV)are energy 20 times in Pt13/B-g and Pt13/N-g, respectively, andFermi level is shift to zero  

Fig. 3 Interaction between Pt catalyst and doped graphene: a binding energy (Eb); b AC between Pt atom and C/B/N; c average netcharge (DQ(e)) of Pt (± denotes gaining/losing electrons); d geometrical parameters of bond length of Pt-C and Pt-B/N  

Fig. 4 a Adsorption energy between CO/O2 and Ptn/X-g (X = B, N, and C); b positions of d-band center calculated for Ptn/X-g (X = B,N and C) clusters as a function of cluster size; c illustration of energy level shifts between O2 and Ptn/X-g (X = C, B, N); relationshipbetween O2 adsorption energy and parameters: d QO2, e hPt, and f CN; relationship between CO adsorption energy and parameters:g CN, h hPt, and i n  

Fig. 5 Potential energy curves for CO oxidation promoted by a Pt4/B-g, b Pt5/B-g, and c Pt6/B-g along Path 1 (black line) and Path 2(red line), respectively, where energies include zero-point energy corrections      

审核编辑 ：李倩