Abstract Paper waste sludge (PWS) generated by the pulp and paper industry is a cellulose-rich residue that remains largely underutilized and presents disposal challenges. In this study, an integrated chemical–biological process was developed to valorize PWS into high-value bacterial cellulose (BC) through sulfuric acid–catalyzed hydrolysis followed by fermentation with Acetobacter xylinum. The hydrolysis step was statistically optimized using a Box–Behnken design to evaluate the effects of solid-to-liquid ratio, sulfuric acid concentration, temperature, and reaction time on reducing sugar production. The optimal hydrolysis conditions were identified as a solid-to-liquid ratio of 1:31.2, sulfuric acid concentration of 8.17%, temperature of 91.3 °C, and reaction...

Abstract In this work, TiO2@g–C3N4 was synthesized and formulated as a novel ready-to-use screen-printable paste for water splitting applications. Various analytical methods were employed to examine the composition, morphological characteristics, and optical properties of the individual materials and the resulting heterojunction. Photoelectrochemical (PEC) water splitting was investigated under illumination of 100 mW cm-2 using linear chopped-light chronoamperometry (CA) and linear sweep voltammetry (LSV) techniques. The results affirmed the successful fabrication of TiO₂@g–C₃N₄ heterojunction photoelectrodes. The sample prepared using a paste containing 15% g–C₃N₄ (TO@CN15) exhibited a significant enhancement in photocurrent response. The OER achieves 10 mA cm⁻² at an impressively low overpotential...