Catalyzed Hydrolysis of Tetrahydroxydiboron by Graphene Quantum Dot-Stabilized Transition-Metal Nanoparticles for Hydrogen Evolution

Abstract

The search of new H2 evolution systems avoiding fossil sources and their mechanisms is a priority in the 21st century society. Hydrolysis of tetrahydroxydiboron (TDB), a current borylation source in the literature, is used here for H2 evolution for the first time. It is catalyzed by graphene quantum dot-stabilized nanoparticles (NPs). With RhNP- or PtNP-catalyzed reactions, D2 formation from D2O confirms that water is the only hydrogen source. Kinetic isotopic effects yield k H/k D = 5.91 and 4.18, strongly suggesting double water O–H bond cleavage on the NP surface in the rate-limiting step. The most efficient catalysts are the RhNP and PtNP (total turnover frequencies: 3658 and 4603 molH2 ·molcat –1·min–1, respectively). The order of catalytic activity is as follows: PtNP > RhNP > AuNP > PdNP > IrNP > RuNP, and a catalytic mechanism of TDB hydrolysis is proposed.

Facile synthesis of graphene quantum dots from glucan and their application as a deoxidizer and in cell imaging

“…In this study, GQDs had been synthesized from the commercial polymer glucan and water, according to our previous work. 29,30 The AuNPs have been successfully synthesized by mixing of GQDs and Au(III) salts without any additional reductants. Finally, the as-synthesized GQDs have been successfully applied in cell imaging due to their favorable hydrophilicity, excellent biocompatibility, highly PL properties, and low cytotoxicity.…”

“…57 As reported in our previous work, when the excitation wavelength is changed from 320 to 480 nm, the corresponding emission peak of GQDs red shifts from 444 to 537 nm in the PL spectra. 29,30 This suggests that the PL processes are mainly influenced by surface defects of the GQDs. 58 The above optical results inspired us to apply the GQDs in biological systems.…”

“…In this study, we used our previously reported GQDs ( Figure 1) with an average size of 2.74 nm, in which the GQDs were synthesized from the commercial polymer glucan and water. 29,30 The GQDs have been successfully used to reduce Au(III) salts for forming AuNP without any additional reductants. Finally, the as-synthesized GQDs have also been successfully applied in cell imaging, due to their favorable hydrophilicity, excellent biocompatibility, highly PL properties, and low cytotoxicity.…”

Acid‐ and Base‐Catalyzed Hydrolytic Hydrogen Evolution from Diboronic Acid

“…In this respect, another commercially available class of boron compounds, diboronic acid and esters, B 2 X 4 (X=OH and pinacolate, pin, respectively) [5] has shown great usefulness in organic synthesis, [6] in particular for hydrogenation and cross coupling with haloarenes producing arylboronic derivatives that are well known as precursors of C−C bonds upon Miyaura‐Suzuki coupling [7] . These two diboron derivatives have indeed largely been used in transition‐metal‐catalyzed transfer hydrogenation of a variety of substrates using water as the hydrogen source, [8] and H 2 has been found as intermediate [9] or product [10] in some of these reactions.…”

Sonochemical Synthesis of Differently‐Sized Nanoparticles of a Silver(I) Compound: An Optical, Anticancer, and Thermal Activity Evaluation Study

“…[6] The incorporation of nanomaterials into a wide range of applications is motivated by diverse properties, [7] such as medical, [8] thermal, [9] sensor, [10] energy storage, [11] catalyst. [12] Nanomaterials offer unique size-dependent physical and chemical properties that cannot be observed in their bulk analogs due to their tunability in particle size, shape, deformability, and surface charge/ ligand/hydrophilicity. [13] Various features such as size, shape, and surface chemistry of nanoparticles (NPs), cell line type, and cell culture media are involved in penetration into cell membrane and following that induced disruption.…”