Akademik Məlumat İdarəetmə Sistemi
CASE STUDIES IN THERMAL ENGINEERING, vol.77, 2026 (SCI-Expanded, Scopus)
Coal fly ash (CF), a major industrial by-product rich in metal oxides, offers significant potential for circular-economy applications when repurposed as a low-cost catalyst in clean-energy processes. However, naturally occurring CaSO4 and the SiO2 shell structure in CF limit its catalytic performance. This study introduces an acid-alkali modification strategy using HF and NaOH to enhance CF's catalytic activity for environmentally responsible hydrogen (H2) production during coal steam gasification. The NaOH-HF treatment effectively removed CaSO4 and disrupted the SiO2 layer, releasing embedded iron species (alpha-Fe and alpha-Fe2O3) and generating an active Fe-based phase (FeFy). These transformations strengthened surface functional groups, increased accessible C-H bonds, and significantly accelerated gasification reactions. The modified CF catalyst promoted stronger interactions with steam and coal, enabling more efficient cleavage of O-H and C-H bonds and resulting in higher H2 yields. Hydrogen production increased from 915.99 mL/g for the E-A modification route to 1537.74 mL/g for the A-E route, achieving a carbon-conversion rate of 99.68 %. This work demonstrates how waste-derived catalysts advance both the hydrogen economy and environmental responsibility by transforming industrial waste into a highperformance material for sustainable coal gasification.