Palladium single atoms from melting nanoparticles on WO3−x for boosted hydrogen evolution reaction

The formation process of Pd single atoms synthesized by the thermally melting Pd nanoparticles on an oxygen-vacancy-rich tungsten-oxide matrix at reduction atmosphere was investigated by near ambient pressure X-ray photoelectron spectroscopy. The as-obtained zero-valence Pd single-atom catalyst exhibits a markedly boosted HER activity than those of Pd nanoparticles.