Visible–Near-Infrared-Light-Driven Oxygen Evolution Reaction with Noble-Metal-Free WO₂–WO₃ Hybrid Nanorods

Understanding and manipulating the one half-reaction of photoinduced hole-oxidation to oxygen are of fundamental importance to design and develop an efficient water-splitting process. To date, extensive studies on oxygen evolution from water splitting have focused on visible-light harvesting. However, capturing low-energy photons for oxygen evolution, such as near-infrared (NIR) light, is challenging and not well-understood. This report presents new insights into photocatalytic water oxidation using visible and NIR light. WO₂–WO₃ hybrid nanorods were in situ fabricated using a wet-chemistry route. The presence of metallic WO₂ strengthens light absorption and promotes the charge-carrier separation of WO₃. The efficiency of the oxygen evolution reaction over noble-metal-free WO₂–WO₃ hybrids was found to be significantly promoted. More importantly, NIR light (≥700 nm) can be effectively trapped to cause the photocatalytic water oxidation reaction. The oxygen evolution rates are even up to around 220 (λ = 700 nm) and 200 (λ = 800 nm) mmol g^–1 h^–1. These results demonstrate that the WO₂–WO₃ material is highly active for water oxidation with low-energy photons and opens new opportunities for multichannel solar energy conversion