In situ /photoinduced fabrication of Zn/ZnO nanoscale hetero-interfaces with concomitant generation of solar hydrogen

• Published in: New journal of chemistry Vol. 47; no. 15; pp. 7312 - 7317
• Main Authors: Mangrulkar, Priti A., Manwar, Nilesh R., Chilkalwar, Anushree A., Deshpande, Aparna S., Rayalu, Sadhana S.
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 11.04.2023
• Subjects: Current carriers; Hydrogen; Hydrogen evolution reactions; Hydrogen production; Illumination; Metal oxides; Nanoparticles; Optoelectronics; Photoelectric effect; Photovoltaic cells; Synthesis; Zinc oxide
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/D2NJ05431K

In the present investigation, we report the formation of a metal–metal oxide (Zn/ZnO) nanoscale heterointerfac with concomitant hydrogen generation. The synthesis process is simple and involves the optical illumination of Zn nanoparticles (Zn(NP)) suspended in water. The concomitant hydrogen (H 2 ) evolution during synthesis was found to be linear, and it is dependent on the growth of the Zn/ZnO nano interface. The progressively increasing amount of ZnO relative to Zn(NP) was a limiting factor in H 2 evolution. Two different Zn/ZnO nanoscale heterointerfaces were created and samples were extracted at two different stages of the illumination process. The first sample, extracted from the most reactive illumination phase and named Zn(NP)/ZnO-R, had the highest hydrogen evolution reaction (HER) rate. The second sample, extracted from a less reactive illumination phase and named Zn(NP)/ZnO-S, had a lower HER rate. These in situ (solar light-induced) samples were characterized by XRD, HRTEM, and other methods. The optoelectronic features and the photoelectrochemical (PEC) investigations showed the optimal light-harvesting ability of Zn(NP)/ZnO-R and the effective separation of photoexcited charge carriers, leading to remarkable HER performance. During the visible-light-induced ( in situ ) conversion of Zn(NP) to Zn(NP)/ZnO-R, a concurrent HER rate of 1115 μmol h −1 was observed. Indeed, the photocurrent density value of the Zn(NP)/ZnO-R catalyst is significantly higher than that of Zn(NP)/ZnO-S, pristine Zn(NP), and ZnO. Thus, this study provides new insights into the optimal fabrication of the Zn(NP)/ZnO interface for PEC application with concomitant solar hydrogen generation.