Efficient Low-temperature Hydrogen Production by Electrochemical-assisted Methanol Steam Reforming.

Methanol steam reforming (MSR) provides an alternative way for efficient production and safe transportation of hydrogen but requires harsh conditions and complicated purification processes. In this work, an efficient electrochemical-assisted MSR reaction for pure H2 production at lower temperature (~140 °C) is developed by coupling the electrocatalysis reaction into the MSR in a polymer electrolyte membrane electrolysis reactor. By electrochemically assisted, the two critical steps including the methanol dehydrogenation and water-gas shift reaction are accelerated, which is attributed to decreasing the methanol dehydrogenation energy and promoting the dissociation of H2 O to OH* by the applied potential. Furthermore, the reduced H2 partial pressure by the hydrogen oxidation and reduction process further promotes MSR. The combination of these advantages not only efficiently decreases the MSR temperature but also achieves the high rate of hydrogen production of 505 mmol H2 g Pt -1 h-1 with exceptionally high H2 selectivity (99 %) at 180 °C and a low voltage (0.4 V), and the productivity is about 30-fold than that of traditional MSR. This study opens up a new avenue to design novel electrolysis cells for hydrogen production.

Ultra-Low-Potential Methanol Oxidation on Single-Ir-Atom Catalyst.

Methanol oxidation plays a central role to implement sustainable energy economy, which is restricted by the sluggish reaction kinetics due to the multi-electron transfer process accompanied by numerous sequential intermediate. In this study, an efficient cascade methanol oxidation reaction is catalyzed by single-Ir-atom catalyst at ultra-low potential (<0.1 V) with the promotion of the thermal and electrochemical integration in a high temperature polymer electrolyte membrane electrolyzer. At the elevated temperature, the electron deficient Ir site with higher methanol affinity could spontaneous catalyze the CH3OH dehydrogenation to CO under the voltage, then the generated CO and H2 was electrochemically oxidized to CO2 and proton. However, the methanol cannot thermally decompose with the voltage absence, which confirm the indispensable of the coupling of thermal and electrochemical integration for the methanol oxidation. By assembling the methanol oxidation reaction with hydrogen evolution reaction with single-Ir-atom catalysts in the anode chamber, a max hydrogen production rate reaches 18 mol gIr -1 h-1, which is much greater than that of Ir nanoparticles and commercial Pt/C. This study also demonstrated the electrochemical methanol oxidation activity of the single atom catalysts, which broadens the renewable energy devices and the catalyst design by an integration concept.

Superior CO2 uptake on nitrogen doped carbonaceous adsorbents from commercial phenolic resin.

In this study, N-doped porous carbons were produced with commercial phenolic resin as the raw material, urea as the nitrogen source and KOH as the activation agent. Different from conventional carbonization-nitriding-activation three-step method, a facile two-step process was explored to produce N-incorporated porous carbons. The as-obtained adsorbents hold superior CO2 uptake, i.e. 5.01 and 7.47 mmol/g at 25 °C and 0 °C under 1 bar, respectively. The synergistic effects of N species on the surface and narrow micropores of the adsorbents decide their CO2 uptake under 25 °C and atmospheric pressure. These phenolic resin-derived adsorbents also possess many extremely promising CO2 adsorption features like good recyclability, quick adsorption kinetics, modest heat of adsorption, great selectivity of CO2 over N2 and outstanding dynamic adsorption capacity. Cheap precursor, easy preparation strategy and excellent CO2 adsorption properties make these phenolic resin-derived N-doped carbonaceous adsorbents highly promising in CO2 capture.

Catalysts and electrolyzers for the electrochemical CO2 reduction reaction: from laboratory to industrial applications.

To cope with the urgent environmental pressure and tight energy demand, using electrocatalytic methods to drive the reduction of carbon dioxide molecules and produce a variety of fuels and chemicals, is one of the effective pathways to achieve carbon neutrality. In recent years, many significant advances in the study of the electrochemical carbon dioxide reduction reaction (CO2RR) have been made, but most of the works exhibit low current density, small electrode area and poor long-term stability, which are not suitable for large-scale industrial applications. Herein, combining the research achievements obtained in laboratories and the practical demand of industrial production, we summarize recent frontier progress in the field of the electrochemical CO2RR, including the fundamentals of catalytic reactions, catalyst design and preparation, and the construction of electrolyzers. In addition, we discuss the bottleneck problem of industrial CO2 electrolysis, and further present the prospect of the essential issues to be solved by the available technology for industrial electrolysis. This review can provide some basic understanding and knowledge accumulation for the development and practical application of electrochemical CO2RR technology.

Pt-Based Rare Earth Alloy as Efficient and Robust Electrocatalyst for High-Temperature Proton Exchange Membrane Fuel Cells.

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) are crucial in future energy systems. However, the activity and stability of the electrocatalysts are severely restricted by high temperature and phosphoric acid poisoning. Herein, PtCe alloy as oxygen reduction reaction (ORR) electrocatalyst for HT-PEMFCs exhibits fantastic performance. Ce can increase the electronic density of Pt, weakening phosphoric acid poisoning and improving ORR activity. The optimized electronic structure can also reduce the dipole effect between Pt and O, which suppresses the irreversible oxidation of Pt. Additionally, the dramatically negative heat of formation in PtCe catalyst brings high kinetic barrier of metal diffusion and dissolution. With this electrocatalyst, the HT-PEMFCs show a preeminent peak power of 605 mW cm-2 with 0.3 mgPt cm-2 . After 30000 cycles of accelerated stability test, the peak power density only decreases by 31.6%, achieving the goal of Department of Energy in 2020 (<40% loss).