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Highly efficient and robust electrocatalysts intended for the oxygen evolution reaction (OER) are essential for energy conversion devices; the structural and morphological fractions of the electrocatalyst can also greatly influence the OER performance. Therefore, developing a high-performing electrocatalyst with desired properties is crucial through a simple and cost-effective chemical process. So, the binder-free, hydrous cobalt phosphate (Co3(PO4)2.nH2O) thin film electrocatalysts are prepared via the successive ionic layer adsorption and reaction (SILAR) method onto stainless steel (SS) substrates at ambient temperature. Additionally, the impact of annealing on the OER efficiency of thin film electrodes made of hydrous cobalt phosphate was observed by subjecting the electrocatalysts to different temperatures (200°C and 400°C). The SILAR synthesized hydrous Co3(PO4)2.nH2O with the short-range ordered agglomerated particles transformed into discrete nanoparticles with an annealing temperature. The as-prepared hydrous cobalt phosphate (CP) demonstrated outstanding OER performance with the least overpotential (η) of 265 mV at 10 mA cm-2 current density and the lowest Tafel slope of 37 mV dec-1, and the overpotential ( η 10 ) increased upon the annealing of catalysts (CP 200 and CP 400). Moreover, the as-prepared electrocatalyst demonstrated overall water splitting at the lowest potential of 1.56 V (@10 mA cm-2) in the alkaline electrolysis system (CP//Pt). The present study reveals that the electrocatalytic performance of the as-prepared cobalt phosphate thin film catalyst is significantly associated with the hydrous content present in catalysts and demonstrates the practical applicability of SILAR-synthesized binder-free cobalt phosphate thin film electrocatalysts. [ABSTRACT FROM AUTHOR]

The objective of this study was to report electrocatalytic activity of tin selenide (SnSe) for oxygen evolution process (OER) and hydrogen evolution reaction (HER). Simple and inexpensive SnSe thin films were deposited onto a steel substrate using an electrodeposition method. Orthorhombic SnSe required a low overpotential value of 325, 317, 314 mV for OER and a low overpotential value of 273, 219, 194 mV for HER for SnSe-1, SnSe-2, and SnSe-3 electrodes, respectively, to reach a current density of 10 mA/cm2. The thickness of thin film increased over time 50, 60, and 70 min for each successive SnSe-1 to SnSe-3 samples. SEM image indicated crystalline in nature with compact grain-like morphology on the entire surface of the substrate. The SnSe-3 sample displayed low Tafel slopes of 90 and 68 mV/dec for OER and HER, respectively. EDX showed that atomic percentage ratio of Sn: Se was 54:46 for SnSe-3 thin film. Overall results suggest that electrochemically synthesized SnSe is a promising candidate as an efficient electrocatalyst for overall water splitting. [Display omitted] • Electrodeposited SnSe thin films were successfully synthesized. • The influence of deposition time on catalytic performance was examined. • Electrocatalytic analysis of SnSe was performed to capabilities of OER and HER. • The catalytic activity exhibited stability over a period of 12 h. [ABSTRACT FROM AUTHOR]

Efficient and durable electrocatalysts are crucial for energy conversion devices that perform the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The structural and morphological characteristics of the electrocatalyst can significantly impact the HER/OER performance. Therefore, it is essential to develop a high-performing electrocatalyst with desired properties using a simple and cost-effective chemical process. So, herein, successive ionic layer adsorption and reaction (SILAR) deposited amorphous, hydrous cobalt iron phosphate (CFP) thin film electrocatalysts are implemented toward electrochemical water splitting. Moreover, in the present work, the molar proportions of cobalt and iron were streamlined to study their synergistic effect on electrochemical HER and OER performance. The electrode of best-performing (CFP–S2) requires the lowest overpotentials of 242 mV for OER and 67.9 mV for HER at a current density of 10 mA/cm2, which maintains its activity after 24 h. The alkaline water splitting into a similar electrolytic bath using two electrode systems was demonstrated for 100 h with the lowest overpotential of 1.72 V. The remarkable electrochemical performance and postmortem analysis unambiguously demonstrate that CFP electrodes are a highly promising and robust option for long-duration water-splitting devices, and the facile SILAR method for scalable CFP electrode synthesis indicates enormous potential for commercial applications. The facile chemical synthesis successive ionic layer adsorption and reaction (SILAR) method employed in this study yields promising results, highlighting the scalable binder-free synthesis and potential for durable electrochemical overall water splitting for clean fuel production. [Display omitted] • Novel synthesis of cobalt iron phosphate (CFP) by SILAR method. • Lower overpotentials for OER (242 mV) and HER (67.9 mV). • Overall water splitting with low potential (1.72 V). • Robustness of material for more than 100 h overall water splitting. • Lab-made device performance with the volume ratio 1:2 for O 2 and H 2 evolution. [ABSTRACT FROM AUTHOR]