依賴于尺寸和載體的Ptn/X-石墨烯催化劑（X = C、B、N）減弱CO中毒

【原文摘要】

一氧化碳中毒是鉑基催化劑應(yīng)用于電催化過程的主要障礙之一。本文基于DFT+D3 計(jì)算，通過B 和N 摻雜石墨 烯并改變團(tuán)簇尺寸以減弱Pt 催化劑的CO 中毒現(xiàn)象。計(jì)算得到了能量上最有利的Ptn/X-石墨烯(X = C, B, N; n = 1?6, 13)結(jié)構(gòu)，且Ptn 和X-石墨烯之間的結(jié)合能依賴于團(tuán)簇尺寸與載體，順序?yàn)椋篜tn/B-g > Ptn/N-g > Ptn/C-g。低 配位及突出的原子作為主要活性位點(diǎn)參與反應(yīng)。由于d 帶中心的位置和界面引起的電子轉(zhuǎn)移，中等大小團(tuán)簇(n = 4?6)能有效抑制CO 中毒，具有優(yōu)異的CO 氧化性能。此外揭示了以第二次CO2 解吸為速控步的E-R 機(jī)制主導(dǎo) 的反應(yīng)路線。Ptn/B-g (n = 4,5,6)對(duì)應(yīng)的活化能壘分別為0.53、0.61 和0.56 eV。這項(xiàng)工作為抗CO 中毒的Ptn/Xg 催化劑在燃料電池中的應(yīng)用與設(shè)計(jì)提供了理論指導(dǎo)。

【圖文速覽】

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

審核編輯 ：李倩