Bio-proton coupled semiconductor/metal-complex hybrid photoelectrocatalytic interface for efficient CO₂ reduction

Abstract

Aimed at high-efficiency biomimetic CO2 photoelectrochemical conversion, a bio-proton coupling metal-complex/semiconductor hybrid photoelectrocatalytic interface (Ru-BNAH/TiO2/Cu2O) was constructed by covalently modifying an in situ proton-transfer functionized molecular catalyst (Ru-BNAH) on the surface of a TiO2/Cu2O composite semiconductor substrate electrode.

Efficient CO2 reduction over a Ru-pincer complex/TiO2 hybrid photocatalyst via direct Z-scheme mechanism

“…Nevertheless, the IR bands of the –COOH/–OH groups in the ONO ligand disappeared for ONO/TiO 2 , suggesting that the ONO ligand may promote the formation of chemical bonding between the –COO group of Ru(N 3 )(ONO)'s ONO ligand and the –OH group of TiO 2 NPs. 13,19 The absorption bands at ∼436/∼800 nm of DRS for the Ru(N 3 )(ONO)/TiO 2 (Fig. 1c) may be an evidence of the chemical bonding, which can promote charge transfer between the two components.…”

“…2d), indicating that the electron cloud density of the carboxylic carbon in the ONO ligand decreases significantly after the Ru(N 3 )(ONO) was loaded on TiO 2 . It implies that the COO– groups disconnect from the Ru 2+ site to chemically bond with the TiO 2 NPs via the –OH groups during the process, 12,13,19 and then the electrons can transfer from the Ru(N 3 )(ONO) toward TiO 2 NPs through the formed COO–Ti bond. Moreover, the C–OH's C 1s BE value increases from 286.6 eV [for Ru(N 3 )(ONO)] to 286.8 eV [for Ru(N 3 )(ONO)/TiO 2 ], also implying that there is electron transfer from the Ru(N 3 )(ONO) to the TiO 2 NPs in the hybrid material.…”

“…Since the pioneering work on Ru, Re, and Ru–Co complexes selectively converting CO 2 to CO/HCOOH in a homogeneous system was reported in 1983, 18 the Ru-based complexes have always been a research hotspot in solar-driven energy conversion due to their excellent catalytic property. 18,19 Nevertheless, these homogeneous systems usually have certain limitations, such as the wide variety of possible products, the need for organic solvents and sacrificial reagents, and the difficulty of photocatalyst recovery. 20–22 Recently, a series of rigid pyridyl-based N′NN ′-Ru( ii ) pincer complexes with good homogeneous CO 2 RR ability were prepared by our group.…”

Hybrid Photoelectrochemical Water Splitting Systems: From Interface Design to System Assembly

“…The hybrid PEC system approach can also be applied to other chemical conversion reactions including CO 2 reduction 171,176–180. Although encouraging progress has been made in the past few years, working examples for water splitting or CO 2 reduction are still largely at the lab‐scale level, far from large‐scale application.…”

Construction of Heterostructured Sn/TiO2/Si Photocathode for Efficient Photoelectrochemical CO2Reduction

“…The high HCOOH yield was reported to be mainly attributed to an effective proton transfer between the BNAH proton carrier and Ru II molecular catalyst through a covalent bond connection under illumination. [9] Especially, co-catalysts such as Bi, [10] In, [11] Ag, [12] or Au, [4] modified on the surface of the semiconductor, can effectively convert CO 2 to more C-products in an aqueous PEC cell. For example, DuChene et al demonstrated that the plasmon-induced hot electrons from Au nanoparticles improved the selectivity of CO product, driving solarto-fuel energy conversion.…”