Maneuvering Intrinsic Instability of Metal Nanoclusters for Boosted Solar-Powered Hydrogen Production

Abstract

Atomically precise metal nanoclusters (NCs) have recently been unleashed as novel photosensitizers but inevitably suffer from light-induced self-transformation to metal nanocrystals (NYs), leading to substantially reduced photoredox activities. Herein, we conceptually demonstrate how to manipulate the intrinsic instability of metal NCs for smartly crafting long-range cascade charge transfer chain assisted by an ultrathin poly­(dialyldimethylammonium chloride) (PDDA) layer that was intercalated at the interface of metal NCs and semiconductor. The unidirectional electron flow endowed by Schottky-type self-transformed metal NYs and unexpected electron-withdrawing capability of PDDA layer concurrently foster the charge transfer cascade, resulting in the markedly enhanced net efficiency of photocatalytic hydrogen evolution performances under visible light irradiation. Our work opens new frontiers for judiciously harnessing the inherent detrimental instability of metal NCs for boosted charge transfer toward solar-to-hydrogen conversion.

Stabilizing atomically precise metal nanoclusters as simultaneous charge relay mediators and photosensitizers

“…Notably, a large number of ultra-small Au x NCs are uniformly deposited on the GR framework, as marked by the yellow circles, but they demonstrate no lattice fringe owing to their generic amorphous properties. 8 Moreover, ultra-thin BPEI encapsulation and Au x NC & CdSe QD codeposition on the GR framework can be strongly corroborated by the elemental mapping result [Fig. 1e-k] and energy dispersive X-ray spectroscopy (EDX) result (Fig.…”

“…2c and Table S1 †), wherein the peak at 1632 cm À1 is derived from the bending vibration mode of carboxyl (C]O) functional groups from GSH ligands capped on the Au x NCs surface. 8 The appearance of the G and D bands in the Raman spectrum of CAG (Fig. 2d) veries successful GR encapsulation in the ternary nanocomposite, and no Au x NCs peaks are visualized.…”

“…[1][2][3][4] However, thus far, only sporadic progress on metal NC-based photosystems has been made owing predominantly to the intrinsic photo-induced instability of metal NCs resulting from ultra-high surface energy. [5][6][7][8][9][10][11][12][13] This retards the advantageous photosensitization efficacy of metal NCs and thus leads to inferior photoactivity. Apart from the necessity to reinforce the photostability of atomically precise metal NCs, ne tuning of charge motion over metal NCs constitutes another key challenge inuencing the development of metal NC-based photocatalysis.…”

Unleashing non-conjugated polymers as charge relay mediators

“…Hydrogen evolution was analyzed on a gas chromatograph (Shimadzu GC-8A) utilizing argon as the carrier gas. The apparent quantum yield (A.Q.Y) and solar-to-hydrogen (S.T.H) conversion efficiency were investigated according to the previous studies based on the following denition: [33][34][35] A:Q:Yð%Þ ¼ number of reacted electrons number of incident photon  100%…”

Tuning atomically precise metal nanocluster mediated photoelectrocatalysis via a non-conjugated polymer

“…Atomically precise metal nanoclusters (NCs, <2 nm) consisting of a definite number of ligands and metal atoms are an emerging subgenre of metal nanomaterials. 1–3 Metal NCs feature molecule-like discrete energy band structures, peculiar atom-packing arrangements, quantum size effect and abundant active sites, 4,5 which endow them with quasi-semiconductor properties such as a highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) transition gap, quantized charging, and strong luminescence, 6–8 thereby diversifying the physicochemical properties of metal NCs for multifarious applications ( e.g. , energy storage and catalysis).…”