The development of techno-economic assessment models for hydrogen production via photocatalytic water splitting

Photocatalytic water splitting using solar radiation is among the promising H2 technologies. Titanium dioxide (TiO2)- and carbon nitride (g-C3N4)-based photocatalysts are the most widely used photocatalytic materials given their activity under visible light and their abundance. Several attempts have been made to improve the photocatalytic performance of these materials in terms of activity level, life span, response to visible radiation, and stability. However, the economic viability of the large-scale deployment of these modifications is not well evaluated in the existing literature. This study develops a bottom-up techno-economic assessment framework to determine the H2 production costs in four alternative pathways: TiO2 nanorods, fluorine-doped carbon nitride quantum dot-embedded TiO2 (CNF: TNRs/TiO2), g-C3N4, and g-C3N4/BiOI composite. Sensitivity and uncertainty analyses were also conducted to understand the impact of input parameters on the hydrogen production cost. The levelized costs of hydrogen (LCOH) are 4.9-0.70+0.75,5.7-0.65+0.45,5.8-1.15+0.55,and7.8-0.95+0.45 USD per kg of H2 produced for TNRs, CNF: TNRs, g-C3N4-S, and BiOI/g-C3N4-S, respectively. In every pathway, the largest contribution is from capital investment and labour costs; together they make up around 75 % of the total cost. Material cost accounts for 13–29 % of the overall cost. The developed information can help in making investment decisions and policy formulation.