Two major challenges, high cost and short lifespan, have been hindering the commercialization process of lowtemperature fuel cells. Professor Wei's group has been focusing on decreasing cathode Pt loadings without losses of activity and durability, and their research advances in this area over the past three decades are briefly reviewed herein. Regarding the Pt-based catalysts and the low Pt usage, they have firstly tried to clarify the degradation mechanism of Pt/C catalysts, and then demonstrated that the activity and stability could be improved by three strategies: regulating the nanostructures of the active sites, enhancing the effects of support materials, and optimizing structures of the three-phase boundary. For Pt-free catalysts, especially carbon-based ones, several strategies that they proposed to enhance the activity of nitrogen-/heteroatom-doped carbon catalysts are firstly presented. Then, an indepth understanding of the degradation mechanism for carbon-based catalysts is discussed, and followed by the corresponding stability enhancement strategies. Also, the carbon-based electrode at the micrometer-scale, faces the challenges such as low active-site density, thick catalytic layer, and the effect of hydrogen peroxide, which require rational structure design for the integral cathodic electrode. This review finally gives a brief conclusion and outlook about the low cost and long lifespan of cathodic oxygen reduction catalysts.

The current or voltage fluctuation in fuel cell operation is harmful to the fuel cell system and power application equipment. Here, we report a technique to eliminate such a fluctuation by the aid of new type of catalysts, superlattice-like mesoporous PtCo catalysts. The current fluctuation in fuel cells catalyzed by two invented catalysts are fixed at as low as 25 mA·cm⁻² with a power of 0.75 W·cm⁻² or 120 mA·cm⁻² with a power of 1.01 W·cm⁻², and no noticeable current decay was detected over 100 h. By contrast, a cell catalyzed by conventional Pt/C catalysts with the same Pt loading delivered a current fluctuation as large as 180 mA·cm⁻² even at low power output of 0.30 W·cm⁻², which also showed 32% current decay rate in 50 h. The superlattices-like mesoporous structure not only enhances the mass transfer and depresses the water flooding but also effectively increases the Pt utilization within its 3D carbon frameworks. Its power output was as high as 11.69 W·mg_Pt⁻¹ (MEA), which is 46.1% higher than the 2025 target of DOE, USA, 8.0 W·mg_Pt⁻¹(MEA).

Bimetallic Pt-skin catalyst is a class of near-surface alloy (NSA) that owns a high degree of control over composition. Herein, density functional theory (DFT) is used to calculate the energetics of oxygen reduction reaction (ORR) on Pt-skin over Ir, Pd and Au substrates. A Brønsted-Evans-Polanyi (BEP) relationship can be determined for the oxygen molecule dissociation. The binding energy of both atomic oxygen and hydroxyl radical is found to correlate well with the d band center of Pt-skin atoms. Their catalytic activities show the volcano relationship as the positions of each substrate in the periodic table. The effect of surface strain, band structure and charge transfer on the d band center is well studied, and it can be found that the surface strain effect plays a dominant role for all Pt-skin catalysts. Ir substrate makes the d band center of Pt-skin go far away from the Fermi level, while Au substrate makes it move towards the Fermi level. Being different from both Ir and Au, Pd substrate makes the d band center of Pt-skin comparable with the monometallic Pt.

The Chinese iron pan can function as a nonstick pan even without a polytetrafluoroethylene (PTFE) coating after a "Kitchen God blessing" seasoning process. We simulate this process and disclose the science behind the "Kitchen God blessing, " finding that through repeated oil-coating and heating, the reversible insertion and extraction of oxygen atoms split the surface of the iron pan, gradually producing Fe₃O₄ nanoballs. These balls give the iron pan a conditional hydrophobicity property, meaning the pan would be hydrophilic when the ingredients contain much water and hydrophobic when they contain less water. The former enables heat to be transferred rapidly through the nanoballs while the latter slows down the heat transference and prevents the pan from sticking. This discovery provides an approach of generating nanoballs on the surface of the metal and also discloses the secret of the fantastic taste produced by cooking with a Chinese iron pan.

Bimetallic platinum-copper (Pt-Cu) alloy nanowires have emerged as a novel class of fuel cell electrocatalysts for oxygen reduction reaction (ORR) due to their intrinsic high catalytic activity and durability, but preparing such electrocatalysts with clean surface via facile method is still a challenge. Herein, PtCu alloy with nanowire networks (NWNs) structure is obtained by a simple modified polyol method accompanied with a salt-mediated self-assembly process in a water/ethylene glycol (EG) mixing media. The formation mechanism of PtCu NWNs including the morphological evolution and the relevant experimental parameters has been investigated systematically. We propose that a micro-interface in H₂O-EG media formed with the assistance of disodium dihydrogen pyrophosphate (Na₂H₂P₂O₇) and its unique nature of coordinating with Pt²⁺ or Cu²⁺ play critical roles in the formation of NWNs. When tested as ORR catalyst, the PtCu_NWNs/C exhibits much higher activity and durability than that of Pt_NWNs/C and commercial Pt/C, even exceeding the target of DOE in 2020. The excellent performance of PtCu_NWNs/C could be attributed to the unique structure of NWNs with 2.4 nm ultrathin wavy nanowires and plentiful surface defects and the modified electronic effect caused by alloying with Cu atoms.

Although polymer electrolyte membrane fuel cells (PEMFCs) have received broad attention due to their virtually zero emission, high power density, and high efficiency, at present the limited stability of the electrocatalysts used in PEMFCs is a critical limitation to their large-scale commercialization. As a type of popularly used electrocatalyst material, carbon black supported platinum (Pt/C)—although highly efficient—undergoes corrosion of carbon, Pt dissolution, Ostwald ripening, and aggregation of Pt nanoparticles (NPs) under harsh chemical and electrochemical oxidation conditions, which results in performance degradation of the electrocatalysts. In order to overcome these disadvantages, many groups have tried to improve the carbon support materials on which Pt is loaded. It has been found that some novel carbon nanomaterials and noncarbon materials with high surface areas, sufficient anchoring sites, high electrical conductivities, and high oxidation resistance under the strongly oxidizing condition in PEMFCs are ideal alternative supports. This review highlights the following aspects: (i) Recent advances in using novel carbon nanomaterials and noncarbon support materials to enhance the long-term durability of electrocatalysts; (ii) solutions to improve the electrical conductivity, surface area, and the strong interaction between metal and supports; and (iii) the synergistic effects in hybrid supports which help improve the stability of electrocatalysts.