The use of solar energy for the photocatalytic degradation of contaminated water is a sustainable strategy. Water scarcity is becoming increasingly critical in semi-arid regions with high solar radiation. In this study, ZnO particles were synthesized using two techniques, hydrothermal and solvothermal, and the obtained materials were named HZ and SZ, respectively. The influence of the synthesis method on the physicochemical properties and photocatalytic activity is reported in detail. The characterization results revealed that the solvothermal method yielded quasi-spherical nanoparticles (62.31 ± 27.95 nm and 88.34 ± 46.71 nm) with a crystallite size of 65 ± 5 nm, a band gap of 3.18 eV, and showed superior textural properties (13.74 m 2 /g) compared to those obtained with the hydrothermal method. The photocatalytic activity was evaluated by the degradation of rhodamine B (RhB) under natural Sunlight (UV-A: 25.18 ± 4.73 and Vis-NIR: 730.73 ± 44.9 W/m 2 ) in Chihuahua city, México. The particles obtained by the solvothermal technique exhibited the highest efficiency under solar radiation conditions, significantly surpassing the HZ sample and conventional UV and visible light sources from lamps. The SZ material was evaluated for reuse testing. This process was carried out for up to 10 consecutive cycles, without treatment after each cycle, and the material demonstrated its potential for industrial applications. Although slight surface contamination slows down the initial reaction kinetics, the material maintained a high final efficiency of 96.5% after 120 min, making it competitive with commercial P25 (TiO 2 ). These experimental results demonstrated the potential of ZnO synthesized by the solvothermal technique as a reusable, cost-effective photocatalyst for water purification under natural solar radiation. • Solvothermal ZnO outperforms hydrothermal samples under natural solar radiation. • Natural sunlight in Chihuahua, México, drives efficient RhB solar degradation. • The SZ catalyst maintains 96.5% efficiency after ten consecutive reuse cycles. • ZnO structural integrity remains after 10 cycles without intermediate washing. • SZ ZnO shows solar efficiency competitive with commercial TiO 2 P25 Degussa.
Paraguay‐Delgado et al. (Thu,) studied this question.