Proton exchange membrane fuel cells convert hydrogen and oxygen into electricity without emissions. The high cost and low durability of Pt-based electrocatalysts for the oxygen reduction reaction hinder their wide application, and the development of non-precious metal electrocatalysts is limited by their low performance. Here we design a hybrid electrocatalyst that consists of atomically dispersed Pt and Fe single atoms and Pt–Fe alloy nanoparticles. Its Pt mass activity is 3.7 times higher than that of commercial Pt/C in a fuel cell. More importantly, the fuel cell with a low Pt loading in the cathode (0.015 mg_Pt cm⁻²) shows an excellent durability, with a 97% activity retention after 100,000 cycles and no noticeable current drop at 0.6 V for over 200 hours. These results highlight the importance of the synergistic effects among active sites in hybrid electrocatalysts and provide an alternative way to design more active and durable low-Pt electrocatalysts for electrochemical devices.

CO₂ electrochemical reduction (CO₂RR) shows great promise in storing renewable energy and alleviating global warming. Its large-scale applications in the industry, however, are still in infant mainly due to the unsatisfactory performance of electrocatalysts. Rational design of advanced electrocatalysts would be the ultimate solution, which has yet to be achieved currently because of the lack of understandings of reaction mechanisms. In the past few years, in situ attenuated total reflection infrared (ATR-IR) spectroscopy has been successfully adopted to study the electrochemical interface of CO₂RR and significantly advanced our understandings of this reaction. In this perspective, these advances, as well as the challenges and opportunities faced in further studying CO₂RR by this technique are discussed.