Rapid charge extraction via hole transfer layer and interfacial coordination bonds on hematite photoanode for efficient photoelectrochemical water oxidation

• Published in: Applied catalysis. B, Environmental Environmental, 2024-12, Vol.358, p.124369, Article 124369
• Main Authors: Niu, Huilin, Gao, Lili, Liu, Mingming, Zou, Yuqi, Wang, Jiaoli, Hu, Guowen, Jin, Jun
• Format: Article
• Language: English
• Subjects: Coordination compound; Hematite photoanode; Hole transfer layer; Interfacial coordination bonds; Photoelectrochemical water oxidation
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2024.124369

Enhancing carrier separation and transport efficiency to achieve efficient water oxidation reaction is an important issue in photoelectrochemical (PEC) water splitting field, and introducing hole transfer layer (HTL) is an effective strategy to improve it. However, the difficulty of charge transfer between HTL and oxygen evolution catalyst (OEC) is a problem unresolved. To ameliorate the situation, we choose CoOOH as HTL and the metal–organic coordination compound constructed by 4,5-Imidazoledicarboxylic acid (IA) and Co/Ni ions as OEC. Using the interfacial coordination bonds as carrier transfer channels, the holes were rapidly extracted from HTL to OEC containing abundant active sites and participate in oxidation reaction. In consequence, the unique design results in a photocurrent density of 2.97 times that of α-Fe2O3 at 1.23 VRHE for the IACN/CoOOH/Fe2O3. This study reveals how the advisable design of photoanode promotes interfacial charge transfer and provides a valuable reference for the design of composite photoanode. [Display omitted] •A highly efficient PEC composite photoanode IACN/CoOOH/Fe2O3 was fabricated by simple methods.•CoOOH was introduced as hole transfer layer to improve charge separation and extraction efficiency.•The holes transfer channels constructed by the interfacial coordination bonds improve the hole transport from HTL to IACN.•The active sites and hydrophilicity of IACN can promote the adsorption and catalysis of active species in the electrolyte.