Guiding Carriers and Steering Spatial Separation via Defect‐Coupled Non‐precious Co‐catalysts for Boosted Photocatalytic H 2 O 2 Production

Artificial photosynthesis offers a promising strategy for the sustainable production of hydrogen peroxide (H 2 O 2 ). However, the practical application of conventional single‐component photocatalysts is often constrained by intrinsic limitations, such as inefficient charge‐carrier separation and transport, which ultimately restrict their overall photocatalytic performance. In this work, we synthesized sulfur vacancy‐engineered CdS (denoted as CdS v ) and constructed a non‐noble metal heterojunction by integrating CdS v with MXene cocatalysts through electrostatic self‐assembly (denoted as: CdS v TC). Under sacrificial agent‐free conditions, the CdS v TC catalyst achieves a high photocatalytic H 2 O 2 production rate of 77.1 μmol·g −1 ·min −1 via a dual‐reaction pathway, primarily driven by the oxygen reduction reaction (ORR) with auxiliary contribution from the water oxidation reaction (WOR). In situ and ex situ X‐ray photoelectron spectroscopy (XPS) characterizations reveal that the enhanced activity originates from the synergistic effects of two mechanisms: trap states created by the introduced S‐vacancies improve the separation and guidance of photogenerated carriers, while MXene cocatalyst enables steering spatial separation and suppresses charge recombination, thereby collectively facilitating the photocatalytic oxygen reduction process. In situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) confirms stabilized oxygenated species on the catalyst surface. Moreover, the CdS v TC sample exhibits an outstanding light‐harvesting capability and high performance under natural solar irradiation and ambient atmosphere, demonstrating great potential for practical application. This study provides a valuable reference for the future design of efficient non‐noble metal heterojunction photocatalysts.