This paper provides a comprehensive review of the temperature control in proton exchange membrane fuel cells. Proton exchange membrane (PEM) fuel cells inevitably emit a certain amount of heat while generating electricity, and the fuel cell can only exert its best performance in the appropriate temperature range. At the same time, the heat generated cannot spontaneously keep its temperature uniform and stable, and temperature control is required. This part of thermal energy can be classified into two groups. On the one hand, the reaction heat is affected by the reaction process; on the other hand, due to the impedance of the battery itself to the current, the ohmic polarization loss is caused to the battery. The thermal effect of current generates Joule heat, which is manifested by an increase in temperature and a decrease in battery performance. Therefore, it is necessary to design and optimize the battery material structure to improve battery performance and adopt a suitable cooling system for heat dissipation. To make the PEM fuel cell (PEMFC) universal, some extreme situations need to be considered, and a cold start of the battery is included in the analysis. In this paper, the previous studies related to three important aspects of temperature control in proton exchange membrane fuel cells have been reviewed and analyzed to better guide thermal management of the proton exchange membrane fuel cell (PEMFC).

Highly active and durable Pd-based electrocatalysts for ethanol oxidation reaction (EOR) play a crucial role in the commercialization of direct ethanol fuel cells (DEFCs). However, the poisonous intermediates (especially adsorbed CO species (CO_ad)) formed during the EOR process can easily adsorb and block the active sites on Pd electrodes, which in turn limits the catalytic efficiency. Hence, we present a series of Pd-based composites with a strong coupling interface consisting of Pd nanosheets and amorphous Bi(OH)₃ species. The incorporation of Bi(OH)₃ can induce an electron-rich state adjacent to the Pd sites and effectively separate the Pd ensemble, leading to excellent CO tolerance. The optimal Pd-Bi(OH)₃ NSs catalyst manifests a mass activity of 2.2 A·mg_Pd⁻¹, which is 5.7 and 2.0 times higher than that of Pd NSs and commercial Pd/C catalyst, respectively. Further CO-stripping experiments and CO-DRIFTS tests confirm the excellent CO tolerance on Pd-Bi(OH)₃ NSs electrode, leading to the enhanced EOR durability.

In the pursuit of sustainable energy solutions, the efficiency of the hydrogen evolution reaction (HER) in alkaline conditions has been a significant challenge, primarily due to the sluggish dissociation of water molecules on platinum (Pt) catalysts. Addressing this critical issue, our study introduces an innovative Pt-Co@NCS catalyst. This catalyst synergistically combines Pt nanoparticles with Co single atoms on a nitrogen-doped carbon scaffold, overcoming the traditional bottleneck of slow water dissociation. Its unique porous concave structure and nitrogen-enriched surface not only provide abundant anchoring sites for Co atoms but also create a conducive hydrophilic environment around the Pt particles. This design leads to a drastic improvement in the water dissociation process, as demonstrated by CO stripping and deuterium labeling experiments. Achieving an outstanding current density of 162.8 mA cm⁻² at −0.1 V versus RHE, a Tafel slope of 26.2 mV dec⁻¹, and a superior nominal mass activity of 15.75 mA μg_Pt ⁻¹, the Pt-Co@NCS catalyst represents a significant step forward in enhancing alkaline HER efficiency, indicating promising advancements in the field.