Nanoporous CoFe2O4 Loaded with Pt-Ag for Photocatalytic Hydrogen Evolution

Nanoporous CoFe2O4 loaded with Pt-Ag was prepared by dealloying melt-spun Al-Co-Fe-Pt-Ag ribbons and then calcining to increase their hydrogen evolution ability. Results revealed that noble Pt and Ag nanoparticles were homogeneously dispersed and loaded on CoFe2O4 nanosheets. When the precursor alloy was Al90.80Co3Fe6Pt0.08Ag0.12, the obtained sample exhibited the highest hydrogen evolution rate of approximately 2.36 mmol/h/g under full-spectrum irradiation, being 24 times that of CoFe2O4 without Pt or Ag. These analyses indicate that using the appropriate amount of Ag could promote visible-light absorption and Pt could serve as an electron sink for effective electron–hole pair separation. Moreover, the Schottky barrier that formed between the Pt-Ag phase and CoFe2O4 effectively suppressed recombination of electron–hole pairs and improved the utilization of photogenerated electrons. Simultaneous loading of Pt and Ag on CoFe2O4 resulted in a synergistic effect that contributed to the performance increase.