Highly Selective and Sharp Volcano-type Synergistic Ni₂Pt@ZIF-8-Catalyzed Hydrogen Evolution from Ammonia Borane Hydrolysis

Abstract

Ammonia borane hydrolysis is considered as a potential means of safe and fast method of H production if it is efficiently catalyzed. Here a series of nearly monodispersed alloyed bimetallic nanoparticle catalysts are introduced, optimized among transition metals, and found to be extremely efficient and highly selective with sharp positive synergy between 2/3 Ni and 1/3 Pt embedded inside a zeolitic imidazolate framework (ZIF-8) support. These catalysts are much more efficient for H release than either Ni or Pt analogues alone on this support, and for instance the best catalyst NiPt@ZiF-8 achieves a TOF of 600 mol·mol·min and 2222 mol·mol·min under ambient conditions, which overtakes performances of previous Pt-base catalysts. The presence of NaOH boosts H evolution that becomes 87 times faster than in its absence with NiPt@ZiF-8, whereas NaOH decreases H evolution on the related Pt@ZiF-8 catalyst. The ZIF-8 support appears outstanding and much more efficient than other supports including graphene oxide, active carbon and SBA-15 with these nanoparticles. Mechanistic studies especially involving kinetic isotope effects using DO show that cleavage by oxidative addition of an O-H bond of water onto the catalyst surface is the rate-determining step of this reaction. The remarkable catalyst activity of NiPt@ZiF-8 has been exploited for successful tandem catalytic hydrogenation reactions using ammonia borane as H source. In conclusion the selective and remarkable synergy disclosed here together with the mechanistic results should allow significant progress in catalyst design toward convenient H generation from hydrogen-rich substrates in the close future.

A Simple and Efficient Device and Method for Measuring the Kinetics of Gas‐Producing Reactions

“…(3)] as a benchmark reaction. This simple reaction proceeds to completion within 30 min at ambient temperature in the presence of catalytic Ru/C, giving no side products . Figure compares the cumulative bubble volumes for our device and a control experiment under identical conditions using an upside‐down burette.…”

“…This simple reaction proceeds to completion within 30 min at ambient temperature in the presence of catalytic Ru/C,g iving no side products. [18][19][20] Figure 3c ompares the cumulative bubble volumes for our device and ac ontrol experiment under identical conditions using an upside-down burette.E ach reaction was repeated in triplicate.I nt he control reaction, we measured 100 points,w hich is highly labour-intensive.The automated device measured at the same time no less than 3000 points with high reproducibility.…”

Robust Synthesis of Gold‐Based Multishell Structures as Plasmonic Catalysts for Selective Hydrogenation of 4‐Nitrostyrene

“…[25,26] NH 3 BH 3 with advantages of high hydrogen storage capacity and long-term stability is an ew candidate as ah ydrogen donor for hydrogenation reactions. [27] We chose the hydrogenation of 4-nitrostyrene as the probe reaction to investigate the influence of surface modification and multishell structure on catalytic performance of Au sphere.T he catalytic reaction was implemented using NH 3 BH 3 as ar educing agent. TheZ rO 2 supported triple-shell Au (PTSAu/ ZrO 2 )a su nmodified contrast sample was also synthesized without addition of PSS (Supporting Information, Figure S11a).…”

In Situ Synthesis of Well‐Ordered Magnetic Palladium Catalyst Triggered by Supramolecular Chaotropic Effect of Boron Cluster

“…1 H NMR spectra were recorded on a Bruker Advance 400 M spectrometer at 400 MHz. 13 C NMR spectra were recorded on a Bruker Advance 400 M spectrometer at 100 MHz. The metal loading amount was determined by inductively couple plasma atomic emission spectrometer (ICP-AES, IRIS Intrepid II; Thermo Elemental, Franklin, USA).…”

“…A good way to solve this problem is immobilizing these metal NPs on a stable support to form metal nanocomposites. In the past few years, many different types of support have been succeeded in fabrication, such as graphene, MOF, polymer, and meso ‐porous silica . Remarkably, Fe 3 O 4 NPs, a new type of magnetic substrate to support metal NPs, have gained extensive attention on account of their excellent nature, such as easy modification and fast recovery .…”