Dopants in the Design of Noble Metal Nanoparticle Electrocatalysts and their Effect on Surface Energy and Coordination Chemistry at the Nanocrystal Surface

Commercialization of energy conversion technologies, such as water electrolysis or fuel cells, has become a common prioritized goal in academia and industry due to the accelerated environmental crisis caused by the rapid increase in demand for fossil fuel-based energy resources. However, these state-of-the-art technologies require the use of expensive noble metal-based electrocatalysts, which significantly undermine the feasibility of their commercial success. The introduction of less expensive elements into the noble metal-based electrocatalysts, namely, doping, has become common in nanocatalysis research because of the lower catalyst preparation costs. Interestingly, recent studies have revealed additional roles of dopants in noble metal catalysts; doping can enhance the catalytic activity and selectivity by modulating the band structure, optimizing the surface energy of the catalysts, controlling the binding strength of adsorbates, and thus affecting the reaction kinetics. Dopants can also intervene in the nanocrystal growth mechanism, leading to shape- and phase-controlled nanocrystals. This review discusses the great versatility of dopants in nanoparticle-based catalysis in all aspects, from nanocrystal growth to nanocatalyst performance. The future challenges and outlook for dopants in nanocrystals and their applications are further discussed.