Metal-free heteroatom doping of carbon nitride for enhanced photocatalytic hydrogen peroxide production

Eneko Sebastian-Garate; Bruna F. GonÃ§alves; Jordi Llusar; Pawel Gluchowski; Ivan Infante; Senentxu-Lanceros Mendez; Qi Zhang; Hugo Salazar

doi:10.1016/j.nanoen.2025.111551

paper

Metal-free heteroatom doping of carbon nitride for enhanced photocatalytic hydrogen peroxide production

arXiv:2605.17897 · doi:10.1016/j.nanoen.2025.111551

Abstract

The photocatalytic production of hydrogen peroxide (H $_{2}$ O $_{2}$ ) from water is a promising strategy for solar-to-chemical energy conversion. Herein, we investigate the effect of metal-free heteroatom doping (B, O, P, and S) on the structural, electronic, and photocatalytic properties of graphitic carbon nitride (C $_{3}$ N $_{4}$ ) for H $_{2}$ O $_{2}$ production under simulated solar irradiation. While pristine C $_{3}$ N $_{4}$ exhibits stacked nanosheets, doping induces disorder, partial exfoliation, and changes in interlayer spacing, confirming successful heteroatom incorporation and modification of the electronic and optical properties. Photocatalytic experiments reveal that H $_{2}$ O $_{2}$ production strongly depends on the sacrificial agent, pH, and reactive-species scavengers. All doped catalysts show enhanced activity compared to pristine C $_{3}$ N $_{4}$ , with 9.6-, 14.8-, 11.0-, and 16.4-fold increases for B-, P-, O-, and S-doped C $_{3}$ N $_{4}$ , respectively. S-doped C $_{3}$ N $_{4}$ achieved the highest H $_{2}$ O $_{2}$ production rate of 3022.1 $I^¼$ mol h $^{- 1}$ g $^{- 1}$ and an apparent quantum yield of 8.1\%, attributed to improved charge separation and optimized selectivity. Mechanistic studies indicate that oxygen activation mainly follows a two-electron (2e $^{-}$ ) pathway driven by charge-carrier modulation and reactive oxygen species dynamics, with singlet oxygen and photogenerated holes playing a dominant role. In addition, S-doped C $_{3}$ N $_{4}$ retained over 95\% of its activity after five cycles. These results highlight metal-free heteroatom doping as an effective strategy for sustainable photocatalytic H $_{2}$ O $_{2}$ generation.

23 pages, 4 figures