Green Synthesis of M⁰ Nanoparticles (M=Pd, Pt, and Ru) for Electrocatalytic Hydrogen Evolution

In recent years the demand for green synthesis and green energy has increased immensely. Herein M⁰ nanoparticles were synthesized using a metal precursor and NaHCO₃ under hydrothermal conditions without using any reducing agent. The nanoparticles were characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Surprisingly, it found that the Pt and Pd nanoparticles contain a high concentration of carbon. The presence of carbon is also evident from the attenuated transmission resonance infra-red (ATRIR) spectroscopy. Moreover, acetic acid was detected as a byproduct of the hydrothermal reaction. NaHCO₃ can be considered as the dissolution of CO₂ in a mildly alkaline solution. Thus, during the reaction, CO₂ was converted to carbonaceous material, which can be considered as a fixation of CO₂. The synthesized nanoparticles are also efficient catalysts for the electrocatalytic hydrogen evolution reaction (HER). It was found that Ru nanoparticles exhibit the highest activity among the three catalysts studied.