Unravelling the Photoelectrochemical Water Splitting of Nanometer-Thick Carbon Nitride Layer

Fengmei Zhi; Suqin Wu; Chen Lai; Mao He; Wenjie Deng; Dexu Zhang; Xiaoying Peng; Qizheng Wu; Jiawei Xia; Zhang-Hui Lu; Mingzhan Wang; Wei-Guang Zhang; Jingsan Xu; Chong Liu; Guiming Peng

doi:10.1002/smll.202401123

Unravelling the Photoelectrochemical Water Splitting of Nanometer-Thick Carbon Nitride Layer

Small. 2024 Apr 25:e2401123. doi: 10.1002/smll.202401123. Online ahead of print.

Authors

Fengmei Zhi¹, Suqin Wu^{1

2}, Chen Lai¹, Mao He¹, Wenjie Deng¹, Dexu Zhang¹, Xiaoying Peng¹, Qizheng Wu¹, Jiawei Xia³, Zhang-Hui Lu¹, Mingzhan Wang⁴, Wei-Guang Zhang², Jingsan Xu⁵, Chong Liu⁴, Guiming Peng¹

Affiliations

¹ College of Chemistry and Chemical Engineering, National Engineering Research Center for Carbonhydrate Synthesis, Key Lab of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, Nanchang, 330022, China.
² GDMPA Key Laboratory for Process Control and Quality Evaluation of Chiral Pharmaceuticals, School of Chemistry, South China Normal University, Guangzhou, 510006, China.
³ Key Laboratory of Advanced Catalytic Materials and Technology, Advanced Catalysis and Green Manufacturing Collaborative Innovation Center, Changzhou University, Changzhou, 213164, China.
⁴ Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA.
⁵ School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.

PMID: 38659372
DOI: 10.1002/smll.202401123

Abstract

Matching the thickness of the graphitic carbon nitride (CN) nanolayer with the charge diffusion length is expected to compensate for the poor intrinsic conductivity and charge recombination in CN for photoelectrochemical cells (PEC). Herein, the compact CN nanolayer with tunable thickness is in situ coated on carbon fibers. The compact packing along with good contact with the substrate improves the electron transport and alleviates the charge recombination. The PEC investigation shows CN nanolayer of 93 nm-thick yields an optimum photocurrent of 116 µA cm^-2 at 1.23 V versus RHE, comparable to most micrometer-thick CN layers, with a low onset potential of 0.2 V in 1 m KOH under 1 sun illumination. This optimum performance suggests the electron diffusion length matches with the thickness of the CN nanolayer. Further deposition of NiFe-layered double hydroxide enhanced the surface water oxidation kinetics, delivering an improved photocurrent of 210 µA cm^-2 with IPCE of 12.8% at 400 nm. The CN nanolayer also shows extended potential in PEC organic synthesis. This work experimentally reveals the PEC behavior of the nanometer-thick CN layer, providing new insights into CN in the application of energy and environment-related fields.

Keywords: carbon nitride; nanolayer; photoelectrochemical cell; solar fuel; water splitting.

Abstract

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