Identification of Halogen-Associated Active Sites on Bismuth-Based Perovskite Quantum Dots for Efficient and Selective CO2-to-CO Photoreduction

Jianping Sheng; Ye He; Jieyuan Li; Chaowei Yuan; Hongwei Huang; Shengyao Wang; Yanjuan Sun; Zhiming Wang; Fan Dong

doi:10.1021/acsnano.0c04659

Identification of Halogen-Associated Active Sites on Bismuth-Based Perovskite Quantum Dots for Efficient and Selective CO₂-to-CO Photoreduction

ACS Nano. 2020 Oct 27;14(10):13103-13114. doi: 10.1021/acsnano.0c04659. Epub 2020 Sep 23.

Authors

Jianping Sheng¹, Ye He¹, Jieyuan Li¹, Chaowei Yuan², Hongwei Huang³, Shengyao Wang⁴, Yanjuan Sun¹, Zhiming Wang¹, Fan Dong¹

Affiliations

¹ Research Center for Environmental and Energy Catalysis, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
² Chongqing Key Laboratory of Catalysis and New Environmental Materials, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 400067, China.
³ National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China.
⁴ College of Science, Key Laboratory of Environment Correlative Dietology of Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China.

PMID: 32940453
DOI: 10.1021/acsnano.0c04659

Abstract

All-inorganic Pb-free bismuth (Bi) halogen perovskite quantum dots (PQDs) with distinct structural and photoelectric properties provide plenty of room for selective photoreduction of CO₂. However, the efficient conversion of CO₂-to-CO with high selectivity on Bi-based PQDs driven by solar light remains unachieved, and the precise reaction path/mechanism promoted by the surface halogen-associated active sites is still poorly understood. Herein, we screen a series of nontoxic and stable Cs₃Bi₂X₉ (X = Cl, Br, I) PQDs for selective photocatalytic reduction of CO₂-to-CO at the gas-solid interface. Among all the reported pure-phase PQDs, the as-synthesized Cs₃Bi₂Br₉ PQDs exhibited the highest CO₂-to-CO conversion efficiency generating 134.76 μmol g^-1 of CO yield with 98.7% selectivity under AM 1.5G simulated solar illumination. The surface halogen-associated active sites and reaction intermediates were dynamically monitored and precisely unraveled based on in situ DRIFTS investigation. In combination with the DFT calculation, it was revealed that the surface Br sites allow for optimizing the coordination modes of surface-bound intermediate species and reducing the reaction energy of the rate-limiting step of COOH^- intermediate formation from ^•CO₂^-. This work presents a mechanistic insight into the halogen-involved catalytic reaction mechanism in solar fuel production.

Keywords: CO2 reduction; active site; perovskite quantum dot; photocatalysis reaction mechanism; selectivity.