Photocatalytic carbon dioxide reduction reaction (CO2RR) represents a promising route for sustainable energy conversion. However, in conventional solid-liquid-gas reaction systems, inefficient CO2 diffusion to the catalyst surface often leads to dominant hydrogen evolution reaction (HER), limiting CO2 conversion efficiency and product selectivity. Herein, we propose a catalyst encapsulation strategy using porous silicon dioxide (SiO2) to spatially control molecular transport toward the active sites. By encapsulating Ag-modified titanium dioxide within a porous SiO2 layer, we effectively restrict water access to the catalytic interface while facilitating CO2 permeation. As a result, the parasitic HER is significantly suppressed, enabling an exceptional 100% selectivity for CO production from photocatalytic CO2 reduction in pure water, which is a dramatic improvement from the mere 5.9% CO selectivity of the unencapsulated Ag-TiO2 catalyst. This design achieves near-complete suppression of HER and 100% selectivity toward CO production under photocatalytic conditions. Our work provides a versatile interfacial engineering approach to overcome mass transfer limitations in three-phase photocatalytic systems, opening avenues for efficient gas-involving photoreactions.
- Open Access
- Article
Porous SiO2 Encapsulation for Selective Suppression of Hydrogen Evolution in Photocatalytic CO2 Reduction
- Junhao Lu 1,
- Yanan Li 1,2,3,
- Yiduo Wang 1,
- Qingqing Guan 1,
- Zixin Ge 1,2,3,
- Yuan Ren 1,2,3,
- Yaohui Zhao 1,2,3,
- Qian Wang 1,
- Mingshang Jin 1,2,3,*
Author Information
Received: 03 Dec 2025 | Revised: 02 Feb 2026 | Accepted: 09 Feb 2026 | Published: 25 Feb 2026
Abstract
Graphical Abstract
Keywords
CO2RR | SiO2 shell | core-shell | HER suppression | interface engineering
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