Leveraging Pd(100)/SnO2 interfaces for highly efficient electrochemical formic acid oxidation

Haiyan Huang; Tianyi Yang; Fang Sun; Zhaohui Liu; Qing Tang; Lingmei Liu; Yu Han; Jianfeng Huang

doi:10.1039/d2nr06142b

Leveraging Pd(100)/SnO₂ interfaces for highly efficient electrochemical formic acid oxidation

Nanoscale. 2023 Feb 2;15(5):2122-2133. doi: 10.1039/d2nr06142b.

Authors

Haiyan Huang¹, Tianyi Yang¹, Fang Sun¹, Zhaohui Liu¹, Qing Tang¹, Lingmei Liu¹, Yu Han², Jianfeng Huang¹

Affiliations

¹ State Key Laboratory of Coal Mine Disaster Dynamics and Control, School of Chemistry and Chemical Engineering, Institute of Advanced Interdisciplinary Studies, Chongqing 400044, China. zhaohui.liu@cqu.edu.cn.
² Advanced Membranes and Porous Materials Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

PMID: 36648401
DOI: 10.1039/d2nr06142b

Abstract

The electrocatalytic formic acid oxidation (FAO) is the crucial anodic reaction of direct formic acid fuel cells (DFAFCs), but its activity remains to be largely improved in order to be practically viable. The rational development of enhanced catalysts requires thorough consideration of various contributing factors that are possibly integrated in composite systems. Here, we demonstrate that, Pd(100)/SnO₂ interfaces, provided being efficiently exploited, can significantly boost FAO activity by a factor of ∼10, compared with pure Pd(100) facets, with the mass activity reaching a record of 14.55 A mg_Pd^-1 at a 40 mV-lower peak potential. Unique Pd/SnO₂ nanocomposites with a myriad of Pd(100)/SnO₂ interfaces were obtained by a newly developed successive seeded growth strategy, wherein pre-formed SnO₂ nanospheres are used as seeds for two-round overgrowth of multitudinous Pd nanocubes. Using electron microscopic, electrochemical, spectroscopic and computational analyses, we found that the Pd(100)/SnO₂ interfaces induce lattice contraction and electron loss on Pd nanocubes, which optimize intermediate binding during FAO. Moreover, we showed that the good cubicity of the Pd nanocubes and the presence of SnO₂ nearby further promote the activity by facilitating the potential-determining step and the elimination of the poisoning CO intermediate, respectively. As such, the combined high intrinsic activity and number density of Pd(100)/SnO₂ interfaces enabled the superior activity of the Pd/SnO₂ nanocomposites. The composite material presented here holds promise for application in DFAFCs, but equally importantly, the insights regarding the structure-performance relationship would be beneficial for designing efficient metal/oxide composite catalysts for diverse electro- and photo-catalytic reactions.