Ag2WO4 based photocatalysts for photodegradation of organic pollutants: a critical review

Abstract

Persistent organic pollutants especially textile dyes and antibiotics contaminate water and fuel antimicrobial resistance, calling for sunlight‑driven, low‑cost remediation. Silver tungstate (Ag₂WO₄) is a visible‑light‑responsive semiconductor with high oxidative potential, but its bare form suffers from fast charge recombination, limited visible absorption, and photocorrosion. This review critically evaluates modification strategies (metal/non‑metal doping, plasmonic Ag decoration, and advanced heterojunctions type‑II, direct Z‑scheme, S‑scheme) that enhance carrier separation and redox selectivity. Representative Ag₂WO₄ composites for dye/antibiotic degradation are compared by band alignment, reactive‑species pathways (·O₂⁻/·OH/h⁺), stability/recyclability, and operating windows, while synthesis routes (hydro/solvothermal, precipitation, ultrasonic, SILAR, solvent‑free, one‑pot) are summarized. Updated figures and tables consolidate morphology, surface area, dosage, pollutant concentration, and light source to enable fair benchmarking. We conclude with challenges (Ag leaching, incomplete mineralization, real‑matrix effects) and research priorities for durable, selective, and scalable Ag₂WO₄ photocatalysts for water treatment.