Pd/CQDs/TiO2–NH2 composite schottky catalyst for efficient hydrogen production from formic acid dehydrogenation under visible light

Abstract

The development of photocatalytic materials with good adsorption capacity and high visible light activity is essential for efficient and stable photocatalytic hydrogen production from formic acid dehydrogenation. The wide band gap of TiO₂ photocatalyst materials limits their application in the field of visible light catalysis. In this work, a new composite material, Pd/CQDs/TiO₂–NH₂, is developed. Here, Pd is attached to amine-functionalized mesoporous titanium dioxide modified with carbon quantum dots (CQDs). This configuration is designed to enhance the catalytic activity for formic acid dehydrogenation when exposed to visible light. The Pd/CQDs-1/TiO₂–NH₂ catalyst exhibited outstanding performance under visible light, achieving a turnover frequency (TOF) of 2666.1 h⁻¹ at 308 K and perfect hydrogen selectivity. Compared to the Pd/TiO₂–NH₂ catalyst with a TOF of 1715.5 h⁻¹, this is a significant improvement. The data implies that the addition of CQDs significantly increases light efficiency, aids in the separation of photogenerated charge carriers, and enhances hydrogen production. Ultimately, the experiments clarified how the combined action of Pd, CQDs, and TiO₂–NH₂ synergistically boosts the catalytic dehydrogenation of formic acid under visible light. The findings present an innovative approach to improving Pd/TiO₂ schottky materials.