An Innovative Water Splitting Process for a Sustainable In Situ Hydrogen Generation–Reduction of Nitrobenzenes Catalyzed by a New Bimetallic Nanocatalyst

In this research, bimetallic CdNi nanoparticles encapsulated in a magnetic spent coffee ground (Fe₃O₄@COFF/CdNi) was synthesized as a new nanocatalyst. The structural and chemical characteristics of Fe₃O₄@COFF/CdNi were comprehensively investigated using various techniques, including FT-IR, XRD, XPS, TEM, VSM, EDS, TGA, BET, and ICP. Through XRD, XPS analysis, TEM images, and EDS mapping, the presence of CdNi nanoalloys was conclusively established. Fe₃O₄@COFF/CdNi exhibited remarkable catalytic activity for the hydrogen generation from water using iso-propanol as a clean sacrificial agent. The high catalytic performance of Fe₃O₄@COFF/CdNi was attributed to the synergistic cooperative effect of Cd and Ni within CdNi nanoalloys. Interestingly, this process was performed for the in situ generated hydrogen from water to reduce a range of nitrobenzenes simultaneously into the corresponding anilines in high yields (93%–98%). The magnetic and hydrophilic characteristics of Fe₃O₄@COFF/CdNi facilitated its reusability over five runs. Using water as the most abundant hydrogen source, for the first time for in situ hydrogen generation–reduction of nitrobenzenes without demanding on external light sources or power supplies can be mentioned as a significant milestone of this field of study.