Solvent-mediated construction of hydrogen bond networks for boosting the photocatalytic performance of AgBr

The development of solar-driven photocatalytic systems for the efficient degradation of water pollutants and the concurrent synthesis of H₂O₂ has emerged as a major research focus in the water treatment domain. In this study, we innovatively constructed a composite hydrogen bond network (DES-like system [Lactic acid/Betaine mixtures]-nanocellulose [CNF]) within a solvent, which provided a high-density and stable synthetic environment. This approach facilitated the formation of additional nucleation sites for the catalyst and inhibited excessive crystal growth. We successfully synthesized small-sized AgBr photocatalysts possessing a surface hydrogen-bonded layer (labeled AgBr-LBCNF). This layer modified the electron cloud distribution around the catalyst, enabling the modulation of its electronic band structure. The effects of pH on the developed system were investigated. The photocatalytic material demonstrated optimal performance at a pH of 5.17 in the LBCNF solution (Lactic acid/Betaine mixture with CNF). Under simulated solar light, the apparent degradation rate constant of the developed catalyst for rhodamine B was 0.114 min^-1, achieving a removal efficiency of 100% within 40 min, which indicated an 11.40-fold increase in performance compared with that of AgBr synthesized in pure water, simultaneously producing approximately 518.46 μmol/g/h of H₂O₂. After 10 cycles, the catalyst retained 94.92% of its initial activity. The regulation of the density of the hydrogen bond network within the solvent environment facilitated the successful development of a photocatalyst that could efficiently degrade organic pollutants and simultaneously yield H₂O₂, providing new insights into the design of solvent systems.