Conspectus
Fuel cells are among the cutting-edge energy
technologies. Their
commercial development is still hindered by noble platinum (Pt) catalysts
for the oxygen reduction reaction (ORR) at the cathode, which not
only determine the energy conversion efficiency and service life but
also are closely related to the cost and broad application of fuel
cells. Given the bright and enormous future of fuel cells, ORR catalysts
should possess highly efficient performance yet meet the acceptable
Pt costs for large-scale application. Extensive efforts are concentrated
on the optimization of Pt-based nanostructures and upgradation of
functional carriers to achieve the low-cost and high-activity Pt-based
catalysts. By improving the Pt utilization and accessible surface,
reducing Pt consumption and catalyst costs, accelerating mass exchange
and electron transfer, alleviating the corrosion and agglomeration
of carriers and Pt, accompanying with the assistance of robust yet
effective functional supports, the service level and life of Pt-based
electrocatalysts would be significantly improved and fuel cells could
get into commercial market covering broader applications.
In
this Account, we focus on the recent development of Pt-based
catalysts to figure out the problems associated with ORR catalysts
in fuel cells. Recent development of Pt-based catalysts is discussed
in different stages: (1) multiscale development of Pt-based nanostructures;
(2) multielement regulation over Pt-based alloy composition; (3) upgradation
of carbon and noncarbon support architectures; (4) development of
integrated Pt-based catalysts for fuel cells. Finally, we propose
some future issues (such as reaction mechanism, dynamic evolutions,
and structure–activity relationship) for Pt-based catalysts,
which mainly involve the preparation strategy of Pt-integrated catalysts
(combination of Pt nanostructures with nanocarbons), performance evaluation
(standard measurement protocols, laboratory-level rotating disk electrode
(RDE) measurements, application-level membrane electrode assembly
(MEA) service test), advanced interpretation techniques (spectroscopy,
electron microscopy, and in situ monitoring), and cutting-edge simulation/calculations
and artificial intelligence (simulation, calculations, machine learning,
big data screening). This Account calls for the comprehensive development
of multiscale, multicomponent, and high-entropy Pt-based alloy nanostructures,
and novel and stable carriers, which provide more available options
for rational design of low-cost and high-performance Pt-integrated
ORR catalysts. More importantly, it will give an in-depth understanding
of the reaction mechanism, dynamic development, and structure–performance
relationship for Pt-based catalysts in fuel cells and related energy
technologies.
