A straightforward and mild protocol for photochemical in situ selective hydrogenation is described via an Al-H2O system as a hydrogen donor and deploying a Pd-g-C3N4 photocatalyst under visible light and ambient conditions. Water, a green solvent, provided hydrogen and the photocatalyst Pd-g-C3N4 facilitated hydrogenation with excellent yield and selectivity for a wide range of olefins and nitro compounds (>99%). The robust catalyst is stable with excellent reusability for five consecutive runs. Besides recognition for its excellent photocatalytic ability, Pd-g-C3N4 has also been introduced as an efficient bifunctional electrocatalyst towards overall water splitting (both the hydrogen evolution and the oxygen evolution reaction) with excellent durability; it can catalyze both half-cell reactions in the same media (0.5 M H2SO4 solution) with Tafel slopes for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) for the catalyst being 36 and 72 mV dec−1, respectively. The enhanced catalytic activities may be due to the synergistic effect among Pd and C and N of the C3N4 material. These findings point to a promising pathway to assemble a robust and efficient catalyst for both photochemical and electrochemical reactions and pave a new avenue for the development of a bifunctional photo/electrocatalyst for hydrogenation and overall water splitting.
Bibliographical noteFunding Information:
The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology of The Hebrew University of Jerusalem is acknowledged. Dr Hani Gnayem and Ofer Lahad are warmly acknowledged for their assistance. Dr S. Sarkar thanks VIT for providing the ‘VIT SEED GRANT’ for carrying out this research work.
© 2022 The Royal Society of Chemistry.