Tuning Ag Loading and Particle Size in Ag@g-C3N4 Photocatalysts for Selective CO2 Conversion to CO and CH4
Year: 2025
Type: article
Abstract: Elucidating the mechanisms of CO2 photocatalytic conversion systems is crucial for tackling the challenges of carbon neutrality. In this study, a series of Ag@g-C3N4 photocatalysts were constructed with metal particle size modulation as the core strategy to systematically reveal the modulation mechanism of Ag nanoparticles (Ag NPs) size variation on the selectivity of CO2 photoreduction products. Systematic characterizations revealed that increasing Ag size enhanced visible light absorption, promoted charge separation, and improved CH4 selectivity. Photocatalytic tests showed Ag3.0%@CN achieved optimal activity and electron utilization. Energy band analyses indicated that Ag modification preserved favorable conduction band positions while increasing donor capacity. Further density-functional theory (DFT) calculations reveal that Ag NPs size variations significantly affect the adsorption stability and conversion energy barriers of intermediates such as *COOH, CO and CHO, with small-sized Ag7 NPs favoring the CO pathway, while large-sized Ag NPs stabilize the key intermediates and drive the reaction towards the CH4 pathway evolution. The experimental and theoretical results corroborate each other and clarify the dominant role of Ag NPs size in regulating the reaction path between CO and CH4. This study provides mechanistic guidance for the selective regulation of the multi-electron reduction pathway, which is of great significance for the construction of efficient and highly selective CO2 photocatalytic systems.
Source: Nanomaterials
DOI: 10.3390/nano15181443
Authors: Shicheng Liu, Na Li, Qulan Zhou
Institution: Xi'an Jiaotong University
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
Award: G2468974709
OpenAlex ID: W4414355384