Engineering a Multifunctional Cu2O/BiVO4@Ti3C2 MXene Z‐Scheme heterojunction for photocatalytic environmental Detoxification, H2 Generation, and CO2 reduction to CO and CH4: Experimental modeling and mechanistic insights

• A ternary Cu 2 O/BiVO 4 @Ti 3 C 2 Z-scheme was synthesized for versatile photocatalysis . • Optimized 30% MXene loading achieved 99.5% TC removal under visible light. • CO 2 reduced to CO (94.92 µmol/g) & CH 4 (41.03 µmol/g), surpassing bare catalysts. • H 2 production reached 4.70 mmol/g/h, ∼4 × higher than pristine Ti 3 C 2 . • Reactive species (•OH, •O 2 – ) dominated via a Z-scheme mechanism enhancing charge separation. Developing advanced semiconductor materials that can concurrently address energy and environmental challenges is critically essential. Herein, a novel Cu 2 O/BiVO 4 @Ti 3 C 2 MXene Z‐scheme photocatalyst was synthesized by a simple chemical reduction route and exhaustively characterized via structural, morphological, optical, and electrochemical analyses. Controlling Ti 3 C 2 MXene loading (optimized at 30 wt%) proved vital to enhancing charge‐carrier mobility and redox potential, whereas higher loadings (>40 wt%) masked active sites and lower loadings (<20 wt%) offered inadequate conductivity gains. Under visible‐light irradiation, Cu 2 O/BiVO 4 @Ti 3 C 2 :30 catalyst displayed remarkable versatility by simultaneously achieving near‐complete tetracycline (TC) degradation, water splitting for H 2 production (4.70 mmol g -1 h −1 ), and CO 2 reduction to CO (94.92 µmol g −1 ) and CH 4 (41.03 µmol g −1 ). These efficiencies exceeded those of bare Cu 2 O, BiVO 4 , Ti 3 C 2 , and the binary Cu 2 O/BiVO 4 system by threefold to fourfold, underscoring the synergistic function of the Z‐scheme heterojunction architecture. The RSM-CCD modeling approach determined the optimal conditions for TC degradation to be 34.51 mg L -1 initial concentration, 1.12 g L -1 catalyst dosage, 70.89 min irradiation time, and pH 4.94, achieving a 99.5 % removal rate. LC–MS results revealed that TC underwent successive oxidative transformations into less harmful intermediates, further corroborated by toxicity assays showing decreased ecological risk of the final products. Mechanistic studies confirmed a Z‐scheme mechanism, wherein Ti 3 C 2 expedited interfacial charge transfer, suppressing recombination and enhancing both reductive (CO 2 ‐to‐fuel, H 2 evolution) and oxidative (antibiotic mineralization) half‐reactions. Furthermore, the catalyst retained its photocatalytic efficacy over multiple cycles, indicating high stability and practical feasibility. Overall, this work highlights the strong potential of MXene‐integrated Z‐scheme photocatalysts for sustainable energy production and environmental remediation, paving the way for next‐generation materials capable of concurrently converting CO 2 , generating H 2 , and decomposing pollutants.