碳载体空位工程助力原位合成的Pt纳米枝晶促进电催化氧气还原  

Vacancy engineering of carbon support strengthens the interaction with in-situ synthesized Pt nanodendrites for boosted oxygen reduction electrocatalysis

作　　者：廖伟 周乾 龙瑾 吴臣中 王彬 彭琼 曹建新[1] 王青梅 Wei Liao;Qian Zhou;Jin Long;Chenzhong Wu;Bin Wang;Qiong Peng;Jianxin Cao;Qingmei Wang(Guizhou University Key Laboratory of Green Chemical and Clean Energy Technology,Guizhou University Engineering Research Center of Efficient Utilization for Industrial Waste,Institute of Dual-carbon and New Energy Technology Innovation and Development of Guizhou Province,School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,Guizhou,China;College of Physics,Guizhou University,Guiyang 550025,Guizhou,China;School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510641,Guangdong,China)

机构地区：[1]贵州大学化学与化工学院,贵州省双碳与新能源技术创新发展研究院,贵州大学工业废弃物高效利用工程研究中心,贵州大学绿色化工与清洁能源技术重点实验室,贵州贵阳550025 [2]贵州大学物理学院,贵州贵阳550025 [3]华南理工大学化学与化工学院,广东广州510641

出　　处：《Chinese Journal of Catalysis》2024年第4期260-271,共12页催化学报（英文）

基　　金：国家自然科学基金(22169005);国家自然科学基金(22068009);国家自然科学基金(22262006);贵州省科技厅科技支撑项目(ZK[2023]050);贵州省科技厅科技支撑项目([2023]403);贵州省双碳与新能源技术创新发展研究院开放项目(DCRE-2023-06)。

摘　　要：质子交换膜燃料电池(PEMFCs)因其高能量密度、低操作温度和环保等特性,被视为极具潜力的能量转换系统.目前,碳载铂颗粒(Pt/C)是PEMFCs阴极氧还原反应(ORR)中使用最广泛的催化剂.然而,Pt与碳载体间的电子结构差异导致Pt纳米颗粒(Pt NPs)易从碳载体上脱落,严重降低了ORR的催化活性.此外,Pt的高成本和稀缺性也限制了其广泛应用.相比之下,Pt纳米枝晶(NDs)因具有高利用率的表面活性位点而备受关注.然而,Pt NDs的合成通常需要严格控制反应条件,且其与碳基底间的弱相互作用易导致活性位点损失和性能下降.因此,开发具有强金属载体相互作用的Pt复合碳催化剂对PEMFCs的实际应用至关重要.本文通过原位Cl-介导的生长策略,结合碳本征空位工程,成功制备了分散在富含碳本征空位的中空氮掺杂碳基底上的Pt NDs催化剂(Pt@HNC-V-800).拉曼光谱和电子顺磁共振光谱结果表明,碳本征空位的形成机制源于碳基底结构中氮原子的耗散,该过程引起碳原子的重新排列,进而产生了丰富的本征缺陷位点.X射线吸收光谱和X射线光电子能谱结果表明,与无碳空位的Pt@HNC催化剂相比,富含本征碳空位的样品(Pt@HNC-V-800)表现出较低的Pt-Pt键配位数(8.64)和更强的给电子效应.得益于Pt NDs丰富的活性位点及其与本征碳空位基底之间的强电子效应,Pt@HNC-V-800的ORR半波电位高达0.947 V,质量活性和比表面活性分别为1.55 A mg^(-1) Pt和1.85 mA cm^(-2),是商用Pt/C的8.2和6.8倍(0.191 A mg^(-1)Pt和0.27 mA cm^(-2)).加速耐久性测试结果表明,经20000次电势循环后,Pt@HNC-V-800的活性无明显变化,其活性损失远低于无碳本征空位的Pt@HNC材料和商业Pt/C催化剂.因此,与无碳本征空位的Pt@HNC材料相比,Pt@HNC-V-800的ORR活性和稳定性都有较大提升,进一步证实了碳本征空位工程协同Pt NDs策略的优越性.此外,密度泛函理论计算结果表明,Pt@HNC-V的丰富�Controlling the morphology of Pt nanostructures can provide a great opportunity to improve their catalytic properties by increasing their active sites and atomic utilization.Here,Pt nanodentrites(NDs)dispersed on intrinsic vacancy-rich hollow nitrogen-doped carbon(Pt@HNC-V)have been successfully prepared through an integrated strategy of in situ Cl-mediated growth and carbon intrinsic vacancy engineering.Raman and electron paramagnetic resonance measurements have demonstrated that our method enables selective transformation of precursors into vacancy-rich samples or vacancy-free ones through a variable etching route.Moreover,X-ray absorption and X-ray photoelectron spectroscopy further verified that the vacancy-rich sample(Pt@HNC-V-800)demonstrates a lower Pt-Pt bond coordination number(8.64)and a stronger electron-donating effect of Pt compared with the vacancy-free Pt@HNC sample.In addition,density functional theory calculations indicate that the vacancy-rich Pt@HNC-V lowers the oxygen overpotential,resulting in optimized adsorption energies of oxygen reduction reaction(ORR)intermediates on Pt NDs and thus yielding improved oxygen reduction reaction activity.Benefiting from Pt NDs with abundant active sites and the strong electronic effect between them and the intrinsic carbon vacancy substrate,the half-wave potential of ORR for Pt@HNC-V-800 is as high as 0.947 V,and the mass activity is 1.55 A mg-1Pt,which is significantly higher than that of commercial Pt/C.The synergy between Pt NDs and carbon intrinsic vacancy engineering can enhance the overall ORR performance,which is beneficial for material preparations in the field of energy and catalysis.

关 键 词：氧还原反应 Pt纳米枝晶 碳本征空位 电催化剂 金属载体相互作用 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TQ426[化学工程] TM911.4[电气工程—电力电子与电力传动]