# Enhanced Photocatalytic CO2 Reduction Performance by External Electric Field‐Driven Charge Separation on Interdigitated Micro‐Spacing Structure

## TL;DR

A new system uses electric fields to improve CO2 reduction by directing charge carriers in a gas-phase reaction.

## Contribution

An electric field-enhanced photocatalytic system using interdigitated electrodes for gas-phase CO2 reduction is introduced.

## Key findings

- A high electric field strength is generated with small voltages using 100 µm spaced interdigitated electrodes.
- Hydrogenated TiO2 achieves four-fold higher CH4 production under applied voltage compared to the baseline.
- The system enables efficient gas-phase CO2 reduction with suppressed charge recombination.

## Abstract

Traditional photoelectrocatalysis (PEC) separates photogenerated charge carriers via an external bias. However, its complex configuration and high‐resistance liquid electrolytes restrict its application largely to liquid‐phase systems. Taking advantage of the remarkable enhancement of the electric field gradient enabled by the interdigitated electrodes (IDEs) with a spacing of 100 µm, an external electric field‐enhanced photocatalytic CO2 reduction system was developed. A relatively high electric field strength can be generated under the application of a small external voltage. Given that the electric field strength is inversely proportional to the electrode spacing, when a 1.0 V is applied to electrodes with a 100 µm spacing, the electric field strength can reach the order of 104 V m−1. By directly applying a modest external voltage (0.5–1.5 V) to hydrogenated TiO2 photocatalysts, an externally induced electric field drives the directional migration of charge carriers, enhancing the separation and transport of photogenerated carriers. At 1.5 V applied voltage, the hydrogenated TK450 catalyst achieves CH4 and C2H6 production rates of 31.1 and 4.9 µmolg−1 h−1, represents a four‐fold enhancement compared to the pristine TiO2 baseline. Consequently, the application of this electric field‐enhanced photocatalytic system to gas‐phase reaction for addressing energy and environmental challenges.

An external electric field‐enhanced photocatalytic system is developed using interdigitated electrodes with 100 µm spacing to overcome the liquid‐phase limitations of traditional PEC. The induced high‐intensity electric field effectively drives the directional migration of charge carriers under low voltage. This strategy significantly suppresses charge recombination and achieves a four‐fold enhancement in CH4 production over hydrogenated TiO2, offering a new approach for efficient gas‐phase CO2 reduction.