The low catalytic activity and poor mass transport capacity of platinum group metal free (PGM‐free) catalysts seriously restrict the application of proton‐exchange membrane fuel cells (PEMFCs). Catalysts derived from Fe‐doped ZIF‐8 could in theory be as active as Pt/C thanks to the high intrinsic activity of FeN4; however, the micropores fail to meet rapid mass transfer. Herein, an ordered hierarchical porous structure is introduced into Fe‐doped ZIF‐8 single crystals, which were subsequently carbonized to obtain an FeN4‐doped hierarchical ordered porous carbon (FeN4/HOPC) skeleton. The optimal catalyst FeN4/HOPC‐c‐1000 shows excellent performance with a half‐wave potential of 0.80 V in 0.5 m H2SO4 solution, only 20 mV lower than that of commercial Pt/C (0.82 V). In a real PEMFC, FeN4/HOPC‐c‐1000 exhibits significantly enhanced current density and power density relative to FeN4/C, which does not have an optimized pore structure, implying an efficient utilization of the active sites and enhanced mass transfer to promote the oxygen reduction reaction (ORR).

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The low catalytic activity and poor mass transport capacity of platinum group metal free (PGM‐free) catalysts seriously restrict the application of proton‐exchange membrane fuel cells (PEMFCs). Catalysts derived from Fe‐doped ZIF‐8 could in theory be as active as Pt/C thanks to the high intrinsic activity of FeN4; however, the micropores fail to meet rapid mass transfer. Herein, an ordered hierarchical porous structure is introduced into Fe‐doped ZIF‐8 single crystals, which were subsequently carbonized to obtain an FeN4‐doped hierarchical ordered porous carbon (FeN4/HOPC) skeleton. The optimal catalyst FeN4/HOPC‐c‐1000 shows excellent performance with a half‐wave potential of 0.80 V in 0.5 m H2SO4 solution, only 20 mV lower than that of commercial Pt/C (0.82 V). In a real PEMFC, FeN4/HOPC‐c‐1000 exhibits significantly enhanced current density and power density relative to FeN4/C, which does not have an optimized pore structure, implying an efficient utilization of the active sites and enhanced mass transfer to promote the oxygen reduction reaction (ORR).

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Developing highly active nonprecious‐metal catalysts for the oxygen reduction reaction (ORR) is of great significance for reducing the cost of fuel cells. 3D‐ordered porous structures could substantially improve the performance of the catalysts because of their excellent mass‐diffusion properties and high specific surface areas. Herein, ordered porous ZIF‐67 was prepared by forced molding of a polystyrene template, and Co‐supported, N‐doped, 3D‐ordered porous carbon (Co‐NOPC) was obtained after further carbonization. Co‐NOPC exhibited excellent performance for the ORR in an alkaline medium with a half‐wave potential of 0.86 V vs. reversible hydrogen electrode (RHE), which is higher than that of the state‐of‐the‐art Pt/C (0.85 V vs. RHE). Moreover, the substantially improved catalytic performance of Co‐NOPC compared with Co‐supported, N‐doped carbon revealed the key role of its hierarchical porosity in boosting the ORR. Co‐NOPC also exhibited a close‐to‐ideal four‐electron transfer path, long‐term durability, and resistance to methanol penetration, which make it promising for large‐scale application.

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Almond-shell-based charcoal was prepared by carbonizing almond shells under nitrogen atmosphere. Nanoporous carbon (NPC) was formed using the obtained activated charcoal by using potassium hydroxide. NPC exhibited a large surface area (1075 m 2 /g), narrow pore-size distribution (1-2 nm). NPC with Nafion was used to modify glassy carbon electrodes to prepare a highly-sensitive electrochemical sensor for simultaneous determination of dopamine (DA) and uric acid (UA) through differential pulse anodic stripping voltammetry (DPV) and cyclic voltammetry (CV). The detection limits (S/N = 3) for DA and UA were estimated to be 0.22 and 0.34μM, respectively. The as prepared electrodes were also used to detect UA and DA in human urine. The experimental data indicated that this easy, low-cost method can facilitate accurate, fast and simultaneous detection of DA and UA.

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