Plasmonic Heterostructure Functionalized with a Carbene-Linked Molecular Catalyst for Sustainable and Selective Carbon Dioxide Reduction

Abstract

Hybridization of homogeneous catalytic sites with a photoelectrode is an attractive approach to highly selective and tunable photocatalysis using heterogeneous platforms. However, weak and unclear surface chemistry often leads to the dissociation and irregular orientation of catalytic centers, restricting long-term usability with high selectivity. Well-defined and robust ligands that can persist under harsh photocatalytic conditions are essential for the success of hybrid-type photocatalysis. Here, we introduce N-heterocyclic carbene as a durable linker for the immobilization of a Rubpy complex-based CO2 reduction site (cis-dichloro-(4,4′-diphosphonato-Rubpy)­(p-cymene) (RuCY)) on a p-type gallium nitride/gold nanoparticle (p-GaN/AuNP) heterostructure. The p-GaN/AuNPs/RuCY photocathode was coupled with a hematite photoanode to drive photoelectrochemical CO2 reduction along with water oxidation. Highly selective CO2 reduction into formates, up to 98.2%, was achieved utilizing plasmonic hot electrons accumulated on AuNPs. The turnover frequency was 1.46 min–1 with a faradic efficiency of 96.8% under visible light illumination (243 mW·cm–2). This work demonstrates that the N-heterocyclic carbene-mediated surface functionalization with homogeneous catalytic sites is a promising approach to increase the sustainability and usability of hybrid catalysts.

Accelerating Electron‐Transfer and Tuning Product Selectivity Through Surficial Vacancy Engineering on CZTS/CdS for Photoelectrochemical CO2 Reduction

“…[ 3 ] Among various reported approaches, photoelectrochemical (PEC) CO 2 reduction has attracted significant attention due to recent significant development of light harvesting semiconductors for direct solar into chemical energy conversion. [ 4,5 ] Many photocathode materials have been reported to obtain various C1C3 products including CO, [ 6,7 ] HCOOH, [ 8,9 ] methanol, [ 10,11 ] ethanol, [ 12,13 ] and propanol. [ 14 ] However, over the past decades, the stumbling block for PEC CO 2 reduction lies in its low efficiency and uncontrolled product selectivity due to the poor light absorption ability, sluggish charge transfer properties, and high overpotential of commonly used photocathode materials, [ 15,16 ] such as Cu 2 O [ 17 ] and ZnTe.…”

Recent Progress and Challenges in Plasmon‐Mediated Reduction of CO2 to Chemicals and Fuels

“…The NHC-RuCY monolayer immobilized on p-GaN/AuNP significantly shifted the product selectivity from CO to CH 4 compared to non-functionalized p-GaN/ AuNP photoelectrodes (Figure 14). [142] Besides metal and semiconductor and some inorganic metal complexes as a functional component in plasmonic hybrid nanostructures, highly porous materials, such as, MOFs, zeolites have appeared as a promising alternative to the lacking catalytic activity of the pristine plasmonic metal nanostructures. [143] Along with the enhanced active surface area, these porous materials address the non-absorbing/low surface affinity of the plasmonic metals toward reactant species by incorporating the variety of analytes to the plasmonic interface through the pores.…”

“…The NHC‐RuCY monolayer immobilized on p‐GaN/AuNP significantly shifted the product selectivity from CO to CH 4 compared to non‐functionalized p‐GaN/AuNP photoelectrodes ( Figure ). [ 142 ]…”

“…The RuCY complex has been immobilized on AuNPs with an N-heterocyclic carbene linker. b) A comparative CO 2 reduction product analysis on NHC-RuCY functionalized and non-functionalized p-GaN/AuNPs photoelectrodes in light and dark conditions.The NHC-RuCY functionalization alters the major product from CO to HCOOH with a higher total amount of products [142]. a,b) Reproduced with permission [142].…”

Progress of GaN‐Based Optoelectronic Devices Integrated with Optical Resonances

“…In 2020, Jun et al proposed the hybridization catalysis structure. [60] In this work, p-GaN/plasmonic AuNPs/ RuCY photocathode was coupled with a hematitie photoanode to drive photoelectrochemical (PEC) CO 2 reduction along with water oxidation. 98.2% of the selective CO 2 was reduced effectively with the assistance of plasmonic hot electrons generated from Au nanoparticles.…”