Photocatalytic H2 evolution from NADH with carbon quantum dots/Pt and 2-phenyl-4-(1-naphthyl)quinolinium ion

Abstract

Carbon quantum dots (CQDs) were simply blended with platinum salts (K2PtCl4 and K2PtCl6) and converted into a hydrogen-evolution co-catalyst in situ, wherein Pt salts were dispersed on the surface of CQDs under photoirradiation of an aqueous solution of NADH (an electron and proton source) and 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh(+)-NA) employed as an organic photocatalyst. The co-catalyst (CQDs/Pt) exhibits similar catalytic reactivity in H2 evolution as that of pure Pt nanoparticles (PtNPs) although the Pt amount of CQDs/Pt was only 1/200 that of PtNPs previously reported. CQDs were able to capture the Pt salt acting as Pt supports. Meanwhile, CQDs act as electron reservoir, playing an important role to enhance electron transfer from QuPh(+)-NA to the Pt salt, which was confirmed by kinetic studies, XPS and HRTEM.

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

“…Not only precious PtNPs but also earth‐abundant CuNPs acted as an H 2 ‐evolution catalyst in the photocatalytic H 2 evolution with use of an organic photocatalyst . In situ generation of PtNPs from K 2 PtCl 6 was also reported for photocatalytic H 2 evolution with composite catalysts of QuPh + ‐NA and carbon quantum dots and those of amorphous carbon and graphitic carbon nitride (g‐C 3 N 4 ) by use of NADH or triethanolamine (TEOA) used as a sacrificial electron donor …”

“…[151,160] In situ generation of PtNPs from K 2 PtCl 6 was also reportedf or photocatalytic H 2 evolution with composite catalysts of QuPh + -NA and carbonq uantum dots and those of amorphous carbon and graphiticc arbon nitride (g-C 3 N 4 )b yu se of NADH or triethanolamine (TEOA) useda sa sacrificial electron donor. [161,162] Self-assembly of monodispersed SiO 2 nanoparticles with the size of 20-30 nm resulted in formation of ad ensely packed monolithic structure containing discrete mesospaces (2-6 nm) among the particles by convective flow through evaporation. [163] The mesospaces can immobilize Rhodamine B, zinc porphyrins, and also even entire enzymes.…”

Clean Donor Oxidation Enhances the H2 Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

“…[1][2][3][4][5] More recently,CQDs have been employed as light harvesters in photocatalytic applications,s uch as the cosensitization of metal oxides in solar cells,p hotodegradation of organic dyes,a nd as photosensitizers in solar fuel synthesis. [6][7][8][9][10][11][12][13] Ar ecent study showed that carboxylate-terminated amorphous CQDs produced by ab ottom-up synthetic method could photosensitize the water soluble molecular nickel H 2 -evolving catalyst NiP (Figure 1). [13] This unique example of aC QD-molecular catalyst hybrid system made use of asacrificial electron donor (ethylenediaminetetraacetic acid (EDTA)) to quench the holes formed upon generation of the photoexcited state,but only achieved afinal TON Ni of 64 with alifetime of 4hours.T his limited stability is assigned to the degradation of NiP during catalytic turnover and/or decomposition through unwanted products generated by the overall reaction scheme-in this case the oxidation products of EDTA.…”

Cu–N Dopants Boost Electron Transfer and Photooxidation Reactions of Carbon Dots

“…[1b] Fortunately,c arbon dots (CDs) shows unique electron transfer and broadband light-absorbing abilities,alarge specific surface area, and are abundant, inexpensive,and nontoxic. [2][3][4][5][6][7][8][9][10][11][12][13] These excellent properties are beneficial to intermolecular electron transfer, which plays akey role in many photooxidation reactions.However, most of the recent research has focused mainly on the emission properties of CDs. [5,6,[10][11][12] There have been few recent efforts devoted to the fabrication of composites based on CDs to enhance their photocatalytic ability.…”