构筑富含磷空位缺陷的磷化钯催化剂实现高效和抗CO毒化的碱性氢氧化反应  

Uleashing efficient and CO‐resilient alkaline hydrogen oxidation of Pd_(3)P through phosphorus vacancy defect engineering

作　　者：杨玉婷 石路岩 梁沁睿 刘奕 董家新 Tayirjan Taylor Isimjan 王宝[3] 杨秀林 Yuting Yang;Luyan Shi;Qinrui Liang;Yi Liu;Jiaxin Dong;Tayirjan Taylor Isimjan;Bao Wang;Xiulin Yang(Guangxi Key Laboratory of Low Carbon Energy Materials,School of Chemistry and Pharmaceutical Sciences,Guangxi Normal University,Guilin 541004,Guangxi,China;School of Environmental Science and Engineering,Sun Yat‐sen University,Guangzhou 510275,Guangdong,China;State Key Laboratory of Biochemical Engineering,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;Saudi Arabia Basic Industries Corporation(SABIC)at King Abdullah University of Science and Technology(KAUST),Thuwal 23955‐6900,Saudi Arabia)

机构地区：[1]广西师范大学化学与药学学院,广西低碳能源材料重点实验室,中国广西桂林541004 [2]中山大学环境科学与工程学院,中国广东广州510275 [3]中国科学院过程工程研究所,生化工程国家重点实验室,中国北京100190 [4]阿卜杜拉国王科技大学的沙特阿拉伯基础工业公司,图瓦勒,沙特阿拉伯

出　　处：《Chinese Journal of Catalysis》2024年第1期176-187,共12页催化学报（英文）

基　　金：国家自然科学基金(52363028,21965005);广西自然科学基金(2021GXNSFAA076001);大学生创新创业训练项目(202210602045);广西研究生教育创新计划项目(YCSW2023140);广西科技基地与人才课题(GUIKE AD20297039).

摘　　要：碱性阴离子交换膜燃料电池(AEMFCs)可以直接将氢的化学能转化为电能,被认为是新兴绿色氢经济的基石技术.但其阳极氢氧化反应(HOR)动力学缓慢,严重依赖于Pt基催化剂.由于Pt基催化剂极易被CO毒化、动力学过程复杂以及价格昂贵,极大限制了其商业化应用.因此,亟需开发高效、稳定和抗CO毒化能力强的新型HOR催化剂.Pd具有与Pt相似的氢键结合能,并且比Pt储量丰富,有望成为实现HOR的候选催化剂.然而,Pd的本征催化活性和Pt相比仍有很大差距.近年来,磷化钯因具有功能多样性和高催化活性被广泛关注.此外,缺陷工程可以有效调控催化剂的表面结构,改善中间体的吸附强度,提高催化剂的催化活性.因此,构建富含缺陷的磷化钯催化剂有望提高其HOR的性能.然而,该方向研究较少,反应机理尚不清楚.因此,阐明空位缺陷对于提高磷化钯催化剂HOR性能的作用机制,对促进AEMFCs电催化反应具有重要意义.本文通过溶胶-凝胶法以及低温磷化策略合成了一种碗状半球结构的富含磷空位Pd3P@C(V_(p)-Pd_(3)P@C)催化剂,并用于碱性HOR.在磷化过程中,通过调整Pd前驱体和磷源比例以及煅烧温度,在碳碗状半球载体上合成具有不同晶相组成(Pd/Pd_(3)P@C,Pd_(3.20)P_(12)@C,Pd_(3)P@C,和Pd_(5)P_(2)@C)的Pd_(x)P_(y)@C催化剂.扫描电镜和透射电镜证实了催化剂为碗状半球形貌.利用电子顺磁共振波谱研究了Pd_(x)P_(y)@C催化剂的磷空位浓度,结果表明,Pd/P比例为1:3时,在350℃下煅烧得到的Vp-Pd_(3)P@C具有最高的磷空位浓度.X射线光电子能谱证实了磷空位促进了d-p轨道杂化,增强了Pd和磷之间的电子相互作用.电化学测试结果表明,Vp-Pd_(3)P@C具有最高的HOR性能,Vp-Pd_(3)P@C在50 mV的质量活性为1.66 mAμg_(Pd)^(–1),交换电流密度为3.2 mA cm^(–2),优于Pd3P(0.45 mAμg_(Pd)^(-1),1.78 mA cm^(–2))和商业Pt/C(0.3 mAμg_(Pd)^(-1),2.29 mA cm^(–2)).同时,该催化�A high-performance and highly CO-resilient hydrogen oxidation reaction(HOR)electrocatalyst is heralded as core material to solve the commercial deployment of hydrogen fuel cells.Phosphorus vacancies,as a type of delicate point defect,could effectively and flexibly modulate the catalytic performance.Therefore,based on the vacancy design philosophy of“less is more”,we synthesize a phosphorus-vacancy-rich Pd_(3)P@C(V_(p)-Pd_(3)P@C)catalyst with bowl-like hemisphere structure for alkaline HOR,for the first time.The Vp-Pd3P@C catalyst exhibits remarkable mass activity and exchange current density of 1.66 mAμgPd^(–1) and 3.2 mA cm^(–2),respectively,surpassing those of Pd3P@C(0.45 mAμgPd^(–1),1.78 mA cm^(–2))and commercial Pt/C(0.3 mAμgPt^(–1),2.29 mA cm^(–2)).Intriguingly,the catalyst can tolerate 1000 ppm CO that Pt/C catalyst lacks.Density functional theory calculations uncover that the optimal local coordination environment and favorable electronic structure that rooted from phosphorus vacancy enable optimum adsorption kinetics of hydrogen and hydroxyl while concomitantly suppressing Pd 4dCO 2π^(*)back donation,contributing to the remarkable HOR reactivity and CO tolerance.

关 键 词：氢氧化反应 CO耐受性 磷空位 V_(p)-Pd_(3)P@C 碗状半球 

分 类 号：O643.36[理学—物理化学]