Hao Wen

Metal-organic frameworks (MOFs) have emerged as attractive electrode materials for applications in energy storage and conversion, owing to their high porosity and surface area. In this communication, we report a hierarchically structured Co-MOF supported on nickel foam (Co-MOF/NF) serving as a high-performance electrode material for supercapacitors. The as-obtained Co-MOF/NF exhibits an ultrahigh areal specific capacitance of 13.6 F cm-2 at 2 mA cm-2 in 2 M KOH, exceeding those of the previously reported MOF-based materials. It also shows an excellent rate performance of 79.4% at a current density of 20 mA cm-2. An asymmetric supercapacitor (ASC) device employing Co-MOF/NF as the positive electrode and activated carbon (AC) as the negative electrode achieves a high energy density of 1.7 mW h cm-2 at a power density of 4.0 mW cm-2 with a capacitance retention of 69.7% after 2000 cycles.

Ammonia borane (AB), a liquid hydrogen storage material, has attracted increasing attention for hydrogen utilization because of its high hydrogen content. However, the slow kinetics of AB hydrolysis and the indefinite catalytic mechanism remain significant problems for its large-scale practical application. Thus, the development of efficient AB hydrolysis catalysts and the determination of their catalytic mechanisms are significant and urgent. A summary of the preparation process and structural characteristics of various supported catalysts is presented in this paper, including graphite, metal-organic frameworks (MOFs), metal oxides, carbon nitride (CN), molybdenum carbide (MoC), carbon nanotubes (CNTs), boron nitride (h-BN), zeolites, carbon dots (CDs), and metal carbide and nitride (MXene). In addition, the relationship between the electronic structure and catalytic performance is discussed to ascertain the actual active sites in the catalytic process. The mechanism of AB hydrolysis catalysis is systematically discussed, and possible catalytic paths are summarized to provide theoretical considerations for the designing of efficient AB hydrolysis catalysts. Furthermore, three methods for stimulating AB from dehydrogenation by-products and the design of possible hydrogen product-regeneration systems are summarized. Finally, the remaining challenges and future research directions for the effective development of AB catalysts are discussed.

Template-directed synthesized Fe_0.1-Ni-MOF nanoarray (Fe_0.1-Ni-MOF/NF) behaves efficiently as an electrocatalyst for alkaline water oxidation with a strong electrochemical durability.

Abstract Single‐atom alloys (SAAs), combining the advantages of single‐atom and nanoparticles (NPs), play an extremely significant role in the field of heterogeneous catalysis. Nevertheless, understanding the catalytic mechanism of SAAs in catalysis reactions remains a challenge compared with single atoms and NPs. Herein, ruthenium‐nickel SAAs (RuNi SAAs ) synthesized by embedding atomically dispersed Ru in Ni NPs are anchored on two‐dimensional Ti 3 C 2 T x MXene. The RuNi SAA‐3 −Ti 3 C 2 T x catalysts exhibit unprecedented activity for hydrogen evolution from ammonia borane (AB, NH 3 BH 3 ) hydrolysis with a mass‐specific activity (r mass ) value of 333 L min −1 g Ru −1 . Theoretical calculations reveal that the anchoring of SAAs on Ti 3 C 2 T x optimizes the dissociation of AB and H 2 O as well as the binding ability of H* intermediates during AB hydrolysis due to the d‐band structural modulation caused by the alloying effect and metal‐supports interactions (MSI) compared with single atoms and NPs. This work provides useful design principles for developing and optimizing efficient hydrogen‐related catalysts and demonstrates the advantages of SAAs over NPs and single atoms in energy catalysis.