Photocatalytic performance of dual-function selenium-enriched biomass-derived activated carbon as a catalyst for dye degradation and hydrogen production

In this work, hemp-derived biochar (BC) was synthesized and then activated with KOH to achieve activated carbon (AC). The selenium (Se 1, 3, 5 wt%) was loaded over AC and characterized using various techniques to investigate the physicochemical, electrochemical, and photocatalytic performance for dye degradation and H2 generation as dual function photocatalyst. BC, AC, and the influence of different loading of Se (1 wt%, 3 wt%, 5 wt%) were examined for the degradation of crystal violet (CV) dye under sunlight. Amongst 3% Se-AC showed the maximum degradation efficiency (98.2%) of CV dye within 75 min and the electrons (e-) had a major contribution to the degradation of CV during the active radical trap test. The photocatalytic H2 production performance was tested and the maximum H2 rate 3095 mu mol/g/h and light to hydrogen efficiency (LTH) 2.36% were achieved for 3% Se-AC. The post-reaction characterization showed competitive stability. A possible reaction mechanism was proposed for photocatalytic H2 production and it is suggested that the Se loading played a key role in charge transfer enhancement due to high polarizability, d-electron richness, and its bond energy with hydrogen atoms (Se-Hads is 273 kJ/mol) is comparable to the platinum (Pt) (Pt-Hads is 251 kJ/mol).