Highly Dispersed Ni Nanoclusters Spontaneously Formed on Hydrogen Boride Sheets

Abstract

Hydrogen boride (HB) sheets are two-dimensional materials comprising a negatively charged hexagonal boron network and positively charged hydrogen atoms with a stoichiometric ratio of 1:1. Herein, we report the spontaneous formation of highly dispersed Ni nanoclusters on HB sheets. The spontaneous reduction reaction of Ni ions by the HB sheets was monitored by in-situ measurements with an ultraviolet-visible spectrometer. Acetonitrile solutions of Ni complexes and acetonitrile dispersions of the HB sheets were mixed in several molar ratios (the HB:Ni molar ratio was varied from 100:0.5 to 100:20), and the changes in the absorbance were measured over time. In all cases, the results suggest that Ni metal clusters grow on the HB sheets, considering the increase in absorbance with time. The absorbance peak position shifts to the higher wavelength as the Ni ion concentration increases. Transmission electron microscopy images of the post-reaction products indicate the formation of Ni nanoclusters, with sizes of a few nanometers, on the HB sheets, regardless of the preparation conditions. These highly dispersed Ni nanoclusters supported on HB sheets will be used for catalytic and plasmonic applications and as hydrogen storage materials.

Controlling Photoinduced H2 Release from Freestanding Borophane Sheets Under UV Irradiation by Tuning B–H Bonds

“…The small diffraction peaks at 27.5°and 28°for the HB-r60 and HB-r90 samples, respectively (Figure S1b, Supporting Information), might originate from unknown by-products and/or stacked HB sheets. [29] The temperature-programmed desorption (TPD) curves (Figure 2a) contain a broad peak up to 1400 K for all samples, consistent with previous reports of HB sheets, [17,21,22,23,24] as well as peaks at 430, 500, and 550 K. The intensity of the 400 K peak was higher for samples with larger XRD peaks, suggesting that the 400 K peak originates from the unknown byproduct and/or stacking of the HB sheets. The TPD peak intensity at 500 K slightly decreased with the volume of resin, whereas the peak at 550 K slightly increased, indicating that the B-H bond becomes stronger in samples prepared with higher volumes of resin.…”

“…The intensity of the light source of the UV–vis device was measured beforehand to obtain a reliable wavelength range for the UV–vis measurements. [ 29 ] UV–vis spectra of the HB sheets in acetonitrile at higher HB concentrations (0.02–12.70 mol L −1 ) were measured by the EEM apparatus.…”

“…[24] They can also reduce specific metal ions to form nanocomposites. [25][26][27][28][29] Notably, hydrogen-deficient HB sheets can adsorb CO 2 and convert it into methane and ethane, even at low temperatures (e.g., 423 K). [30] In addition, theoretical modeling and computer simulations demonstrate that HB sheets are promising candidates for certain applications, such as hydrogen-storage materials, [31][32][33][34][35] battery anode materials, [36][37][38][39] highly selective and sensitive sensors, [40,41] current limiters, [42] and photodetectors.…”

Effective treatment of hydrogen boride sheets for long-term stabilization

“…13 Several studies have confirmed that HB sheets exhibit semimetal electronic properties, 14 superior catalytic properties, [15][16][17][18][19] and specific reductant properties. 17,20,21 Fujino et al demonstrated the ability of HB sheets to catalyze the production of ethylene from ethanol with high selectivity and long-term stability. 15,16 Similarly, Gao et al found that a catalyst prepared with HB and Pt exhibited superior electrocatalytic activity and stability against oxygen reduction compared to commercial Pt/C for proton exchange membrane fuel cells.…”

“…22 HB sheets have redox potentials between À0.277 and À0.257 V versus the standard hydrogen electrode, enabling them to selectively reduce metal ions in solution and form nanoclusters on the sheets. 20,21 This property makes HB sheets useful as reducing agents. Moreover, ultraviolet (UV) irradiation at 300 K can cause H 2 to be released from the HB sheets as a decomposition product, 23 making them a controllable source of H 2 emission.…”