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Optimized porous Pt61Te8Rh31 NR/C with 1D building blocks and 3D surface/interface configurations has been adopted as an advanced high-efficiency fuel cell cathodic catalyst for both ORR and MEA catalysis in PEMFCs.

The nature of many highly efficient catalytic reactions catalyzed by metallocofactors is inspiring. Herein, the concept of metal cofactor was utilized in the in situ fabrication of multiple metal and heteroatom self-doped porous carbonaceous electrocatalysts. The sustainable biomass legume root nodules that contain nitrogenase were used as single precursors, and the specific surface area of the as-prepared catalyst could reach 1835 m2 g−1 by the activation of ZnCl2 during high-temperature pyrolysis processes. The self-doped biomass-derived catalyst exhibits an outstanding oxygen reduction reaction (ORR) electrocatalytic performance with half-wave potentials (E1/2) of 0.723 V and 0.868 V (vs. RHE) in 0.1 M HClO4 and 0.1 M KOH solution, respectively. It is worth noting that E1/2 of the catalyst even outperforms 25 mV to that of Pt/C (E1/2 = 0.843 V) in alkaline electrolytes. This performance is also markedly better than that of most other reference catalysts, which is based on codoped additional transition metals or heteroatoms with biomass-derived carbonaceous materials. The catalyst also delivers promising fuel cell performance in both low-temperature air-breathing polymer electrolyte membrane fuel cells (PEMFCs) and Zn–air batteries. The role of Mo atoms from the iron-molybdenum cofactor in the as-prepared biomass-derived catalyst toward ORRs is discussed herein. This study is expected to inspire exploration and design of appropriate doping structures and compositions to develop highly active and renewable biomass-derived catalysts in diverse application fields.

Formic acid dehydrogenation has attracted plenty of attention lately due to its atom-economical method for hydrogen production. Iridium complexes are outstanding homogeneous catalysts which have high activity and selectivity for formic acid dehydrogenation. However, they cannot be well employed in a controllable hydrogen evolution device due to their resolvability. In this research, we report a series of immobilized iridium complexes for formic acid dehydrogenation. Iridium complexes are immobilized by various insoluble N-incorporated polymers, which make the homogeneous catalysts insoluble in most common solvents. We find that the types of N-incorporated group in the polymers will have great influences on the catalytic activity of the immobilized iridium complexes for formic acid dehydrogenation. The morphology of polymers, like specific surface area and particle size, will have influences on the catalytic activities. The turnover frequency (TOF) is up to 46 000 h−1 at 90 °C when we employ Cp*IrCl2(ppy) for formic acid dehydrogenation. We also make a portable fixed bed reactor for hydrogen evolution with the immobilized iridium complexes which could generate gas at 11.2 mL min−1. The immobilized iridium complexes can realize the hydrogen storage, controllable hydrogen production and hydrogen utilization of formic acid under mild conditions.

A gas diffusion layer (GDL) is one of the essential components of a membrane electrode assembly (MEA), which is the core of proton exchange membrane fuel cells (PEMFCs). However, with the rapid development of PEMFCs, current commercial GDLs are encountering or will encounter many problems, such as complex preparation processes, very high preparation temperature (2000 °C), very high thickness, and high cost. In this research, we developed a simple three-step method to produce a novel flexible, low thickness, low-cost, and high performance GDL by a simple process with low preparation temperatures, low energy consumption and low equipment cost. The three-step method mainly includes creating pores, coating with a microporous layer and heat treatment; it uses only carbon nanotube (CNT) films, CNT powder and polytetrafluoroethylene (PTFE) as the raw materials. The temperature of heat treatment in this research is only 350 °C, which is much lower than 2000 °C required for the preparation of commercial GDLs. The new GDL has many advantages, such as very low thickness (less than 40 μm, only about 1/6 of that of commercial GDL), high flexibility (bending radius < 0.17 mm), low cost and large size (200 mm × 200 mm). Moreover, the overall thickness of the MEA prepared with the new GDL was less than 90 μm, which was only about 1/3 of that of the MEA made with a commercial GDL. Outstandingly, the volume-specific power density of the air-breathing PEMFC made with the new GDL dramatically increased to 15 600 W L−1, and the weight-specific power density reached 9660 W kg−1. It is estimated that the volume-specific power density of the PEMFC stack has potential to be improved by more than 60% by simply replacing the commercial GDL with the new GDL reported in this work. Therefore, this work not only develops a new method for GDL preparation but also provides a new GDL with comprehensive advantages, which is necessary for the next generation of PEMFCs.

Proton exchange membrane fuel cells (PEMFCs) have potential applications in electric vehicles, laptops, and power stations. The catalyst layers in a membrane electrode assembly (MEA) are the core locations in PEMFCs in which to convert the chemical energy of fuels to electrical energy. For a catalyst layer with high performance, it must possess three fast transfer ways to transfer mass (reactants and products), electrons (e−) and protons (H+) quickly and simultaneously. In this work, we greatly improved the performance and lifetime of a fuel cell by constructing these three fast transfer pathways based on a well-ordered and cone-shaped Nafion array with a very high density (5.7 × 108 cones per cm2) using an anodic aluminum oxide (AAO) template. To build a fast pathway for electron transfer, well-dispersed graphene nanosheets were further filled into the Nafion array. After a series of efforts based on the above, the performance of the fuel cell with a cone array as an anode reached 1240 mW cm−2, which is 2.5 times higher than that without an array. Since Pt loading was as low as 17.6 μg cm−2, the mass specific power of Pt was as high as 70.5 kW gPt−1. Consequently, the Pt loading successfully reached the U.S. DOE 2020 target at the anode side, i.e. 25 μg cm−2. In addition, the lifetime of the PEMFC with the cone array is at least 300 h, which is much longer than the 150 h for a PEMFC without an array. Therefore, this work fully exhibits the great potential advantages of using an ordered Nafion array, and is promising to promote the development of the next generation of MEA for use in PEMFCs.

Concerns about the depletion of fossil fuel reserves and environmental pollution make hydrogen an attractive alternative energy source. Here, we first describe a catalytic reaction system that produces H2 from glucose using a homogeneous catalyst [(p-cymene)Ru(NH3)]Cl2 with the maximum TOF = 719 h−1 at 98 °C and an initial pH = 0.5.

As a promising hydrogen storage medium methanol has many advantages such as a high hydrogen content (12.5 wt%) and low-cost. However, conventional methanol–water reforming methods usually require a high temperature (>200 °C). In this research, we successfully designed an effective strategy to fully convert methanol to hydrogen for at least 1900 min (∼32 h) at near-room temperature. The strategy involves two main procedures, which are CH3OH → HCOOH → H2 and CH3OH → NADH → H2. HCOOH and the reduced form of nicotinamide adenine dinucleotide (NADH) are simultaneously produced through the dehydrogenation of methanol by the cooperation of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Subsequently, HCOOH is converted to H2 by a new iridium polymer complex catalyst and an enzyme mimic is used to convert NADH to H2 and nicotinamide adenine dinucleotide (NAD+). NAD+ can then be reconverted to NADH by repeating the dehydrogenation of methanol. This strategy and the catalysts invented in this research can also be applied to hydrogen production from other small organic molecules (e.g. ethanol) or biomass (e.g. glucose), and thus will have a high impact on hydrogen storage and applications.

The fluorescence intensity of a fluorescent molecule can be strongly enhanced when the molecule is near a metal nanoparticle. Hence, fluorescence enhancement has a lot of applications in the fields of biology and medical science. It is necessary to understand the mechanism for such an attractive effect, if we intend to develop better materials to improve the enhancement. In this paper, we directly image the diverse patterns of fluorescence enhancement on single Ag nanoplates by super-resolution microscopy. The research reveals that the edges or tips of the Ag nanoplate usually show a much higher ability of fluorescence enhancement than the mid part. The spatial distribution of fluorescence enhancement strongly depends on the size of the Ag nanoplate as well as the angle between the Ag nanoplate and the incident light. The experimental results above are essentially consistent with the simulated electric field by the theory of localized surface plasmon resonance (LSPR), but some irregularities still exist. We also find that fluorescence enhancement on small Ag nanoplates is mainly due to in-plane dipole plasmon resonance, while the enhancement on large Ag nanoplates is mainly due to in-plane quadrupole plasmon resonance. Furthermore, in-plane quadrupole resonance of large plates has a higher ability to enhance the fluorescence signal than the in-plane dipole plasmon resonance. This research provides many valuable insights into the fluorescence enhancement at the single- and sub-nanoparticle level, and will be very helpful in developing better relevant materials.

The free unpaired electron in Fe(3+) ions cannot be directly removed, and needs a transfer pathway with at least four steps to overcome the high energy barriers to form Fe(4+) ions. Fine changes in the electronic structure of Fe(3+) ions on spin conversion were identified through a deeper analysis of the diffraction, spectral and electrochemical data for six non-planar iron porphyrins. Fe(3+) ions can form four d electron tautomers as the compression of the central ion is increased. This indicates that the Fe(3+) ion undergoes a multistep electron transfer where the total energy gap of electron transfer is split into several smaller gaps to form high-valent Fe(4+) ions. We find that the interchange of these four electron tautomers is clearly related to the core size of the macrocycle in the current series. The large energy barrier to produce iron(iv) complexes is overcome through a gradient effect of multiple energy levels. In addition, a possible porphyrin Fe(3+)˙ radical may be formed from its stable isoelectronic form, porphyrin Fe(3+), under strong core contraction. These results indicate the important role of heme distortion in its catalytic oxidation functions.

This review discusses the latest advances in using single-molecule microscopy of fluorogenic reactions to examine and understand the spatiotemporal catalytic behaviors of single metal nanoparticles of various shapes including pseudospheres, nanorods, and nanoplates. Real-time single-turnover kinetics reveal size-, catalysis-, and metal-dependent temporal activity fluctuations of single pseudospherical nanoparticles (

Pd-Au/C and Pd-Ag/C were found to have a unique characteristic of evolving high-quality hydrogen dramatically and steadily from the catalyzed decomposition of liquid formic acid at convenient temperature, and further this was improved by the addition of CeO(2)(H(2)O)(x).