Temperature-controlled size engineering of CsPbBr3 perovskites for high-performance hydrogen evolution electrocatalysis in alkaline media

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Sustainable hydrogen production requires the development of efficient, low-cost, and stable electrocatalysts. We synthesized CsPbBr 3 perovskite nanocrystals using a hot-injection method at 140, 160, and 180°C, and evaluated their hydrogen evolution reaction (HER) in 1.0 M KOH. A variety of structural and morphological techniques were used to characterize CsPbBr 3 , including X-ray diffraction, transmission electron microscopy, selected-area electron diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, UV–visible spectroscopy, and X-ray photoelectron spectroscopy. In this study, the synthesis temperature strongly influenced the particle size, with the average size of the nanocrystals ranging from 30.86, 166.67, and 186.91 nm at 140, 160, and 180°C, respectively. We encapsulated the perovskite nanocrystals in Nafion and deposited them onto fluorine-doped tin oxide substrates to enhance their stability under alkaline conditions. Among the investigated electrodes, CsPbBr 3 synthesized at 160°C had the best HER activity, requiring an overpotential of 75 mV to reach 10 mA cm −2 and exhibiting a94.2 mV/dec Tafel slope. Based on these results, the Volmer-Heyrovsky pathway seems to be involved in HER kinetics. We evaluated interfacial charge transfer and active site availability using electrochemical impedance spectroscopy and electrochemical surface-area measurements. Further chronoamperometric testing demonstrated stable operation for 4 h in 1.0 M KOH. In the present study, it was demonstrated that CsPbBr 3 -based electrocatalysts benefit from synthesis temperature control for optimizing the structure and HER performance.