One-step synthesis of reduced graphene oxide supported CoW nanoparticles as efficient catalysts for hydrogen generation from NH3BH3

Boosting the Catalytic Performance of NiMoO4 Nanorods in H2 Generation upon NH3BH3 Hydrolysis via a Reduction Process

Although a range of noble metal catalysts, including Ru, Rh, Pd, Pt, and Au, have been developed for efficient H2 generation upon NH3BH3 hydrolysis at room temperature, this is a highly urgent need for exploring earth-abundant metal nanocatalysts for H2 generation upon NH3BH3 hydrolysis. Herein, a NaBH4 reduction strategy was developed to boost the catalytic performance of NiMoO4 nanorods in H2 generation upon NH3BH3 hydrolysis. Indeed, the pristine NiMoO4 nanorods were catalytically inert in NH3BH3 hydrolysis. Significantly, the reduced NiMoO4 nanorods presented excellent catalytic activity in H2 generation upon NH3BH3 hydrolysis, with a turnover frequency (TOF) of 31.2 L(H2)·gcat-1·h-1. Interestingly, the TOF of NH3BH3 hydrolysis over reduced NiMoO4 nanorods significantly increased from 31.2 to 53.6 L(H2)·gcat-1·h-1 under 0.3 M NaOH. The boosting catalytic performance of NiMoO4 nanorods via NaBH4 reduction in H2 generation might be attributed to the higher content of Oads and the formation of nickel boride in the reduced NiMoO4 nanorods. In this work, NH3BH3 hydrolysis over reduced NiMoO4 nanorods was not only used for safe H2 generation but also for its in situ tandem hydrogenation in organic chemistry.

Defect-Rich Co-CoOx -Graphene Nanocatalysts for Efficient Hydrogen Production from Ammonia Borane

Chemical hydrogen storage ammonia borane has attracted extensive attention as a method of efficient utilization of hydrogen energy. The high-efficiency catalysts are the main factor restricting the hydrogen production of ammonia borane. In this paper, the synergistic effect of Co and CoO_x supported on graphene (named Co-CoO_x @GO-II) promotes the efficient hydrogen production of ammonia borane, and its catalytic hydrogen production rate can reach 5813 mL min^-1  g_Co ^-1 at 298 K, the corresponding TOF is 15.33 min^-1 . After five stability tests, Co-CoO_x @GO-II maintained 65% of its original catalytic performance. The synergy of metal and metal oxide and the defects in the atomic arrangement ensure the catalytic activity, the large specific surface area of graphene ensures the dispersion and fixation. This strategy may provide a possibility to design high-performance transition metal catalysts.

Ammonia Borane: An Extensively Studied, Though Not Yet Implemented, Hydrogen Carrier

Ammonia borane H3N−BH3 (AB) was re-discovered, in the 2000s, to play an important role in the developing hydrogen economy, but it has seemingly failed; at best it has lagged behind. The present review aims at analyzing, in the context of more than 300 articles, the reasons why AB gives a sense that it has failed as an anodic fuel, a liquid-state hydrogen carrier and a solid hydrogen carrier. The key issues AB faces and the key challenges ahead it has to address (i.e., those hindering its technological deployment) have been identified and itemized. The reality is that preventable errors have been made. First, some critical issues have been underestimated and thereby understudied, whereas others have been disproportionally considered. Second, the potential of AB has been overestimated, and there has been an undoubted lack of realistic and practical vision of it. Third, the competition in the field is severe, with more promising and cheaper hydrides in front of AB. Fourth, AB has been confined to lab benches, and consequently its technological readiness level has remained low. This is discussed in detail herein.

Highly Dispersed CuNi Nanoparticles Supported on Reduced Graphene Oxide as Efficient Catalysts for Hydrogen Generation from NH3BH3

Highly dispersed CuNi nanoparticles (NPs) immobilized on reduced graphene oxide (RGO) were synthesized via the simple in situ co-reduction of an aqueous solution of Copper(II) sulfate pentahydrate, nickel chloride hexahydrate, and graphene oxide (GO) by the reduction of ammonia borane (AB) at room temperature. The powder XRD, FTIR, EDS, and TEM techniques were used to charaterize the structure, size, and composition of the CuNi/RGO catalysts. The as-prepared CuNi/RGO catalysts showed excellent catalytic performance toward the hydrolysis of AB at room temperature. Compared to Cu/RGO, Ni/RGO, and the RGO-free Cu0.6Ni0.4 counterpart, the as-prepared Cu0.6Ni0.4/RGO catalysts showed much better catalytic activity. Furthermore, kinetic studies showed that the catalytic hydrolysis of AB by Cu0.6Ni0.4/RGO has zero order dependence on the AB concentration, but first order dependence on the catalyst concentration. The turnover frequency (TOF) of Cu0.6Ni0.4/RGO catalyst for the hydrolytic dehydrogenation of AB was determined to be about 20.2 mol H2 (mol Cu0.6Ni0.4/RGO)−1 min−1 at 25 °C. In addition, the activation energy (Ea ) of Cu0.6Ni0.4/RGO was determined to be around 17.7 kJ mol−1, which is one of the lowest activation energy’s of the reported metal-based catalysts.

Cobalt tungsten oxide hydroxide hydrate (CTOHH) on DNA scaffold: an excellent bi-functional catalyst for oxygen evolution reaction (OER) and aromatic alcohol oxidation

CTOHH-DNA, a newly developed catalyst utilized for both electrocatalytic OER and aromatic alcohol oxidation reaction with excellent activities.