Steering Photoelectrons Excited in Carbon Dots into Platinum Cluster Catalyst for Solar‐Driven Hydrogen Production

Abstract

In composite photosynthetic systems, one most primary promise is to pursue the effect coupling among light harvesting, charge transfer, and catalytic kinetics. Herein, this study designs the reduced carbon dots (r‐CDs) as both photon harvesters and photoelectron donors in combination with the platinum (Pt) clusters and fabricated the function‐integrated r‐CD/Pt photocatalyst through a photochemical route to control the anchoring of Pt clusters on r‐CDs' surface for solar‐driven hydrogen (H2) generation. In the obtained r‐CD/Pt composite, the r‐CDs absorb solar photons and transform them into energetic electrons, which transfer to the Pt clusters with favorable charge separation for H2 evolution reaction (HER). As a result, the efficient coupling of respective natures from r‐CDs in photon harvesting and Pt in proton reduction is achieved through well‐steered photoelectron transfer in the r‐CD/Pt system to cultivate a remarkable and stable photocatalytic H2 evolution activity with an average rate of 681 µmol g−1 h−1. This work integrates two functional components into an effective HER photocatalyst and gains deep insights into the regulation of the function coupling in composite photosynthetic systems.

Carbon Dots: A New Type of Carbon-Based Nanomaterial with Wide Applications

“…CDs prepared from different carbon sources or via different synthetic methods always present different absorption behaviors. However, they typically exhibit strong absorption in the ultraviolet (UV) region (200–400 nm), with a tail extending into the visible range, where the absorption bands are assigned to the π–π* transition of the CC bond or the n−π* transition of the CO/CN bond. ,− In particular, some CDs with red or NIR emission usually possess π-conjugated electrons in the sp 2 domains and/or the connected surface groups/polymer chains, which results in their long-wavelength absorption in the range 500–800 nm. ,, Therefore, the absorption features of CDs are mainly affected by types and content of surface groups, size of π-conjugated domains, and variation of the oxygen/nitrogen content in carbon cores.…”

“…CDs are employed as photocatalysts for pollutants degradation (organic dyes, , metal ions, − etc. ), water splitting, ,, CO 2 reduction, , and chemical reactions in the process of solar energy conversion, which are benefitted from their broad light absorption range, from UV to NIR, low cost, excellent photostability, charge separation, and transfer capability. CDs with nitrogen atoms located at the edge sites of the aromatic domains enable efficient interfacial electron transfer and further lead to an increased photocatalytic hydrogen generation from water .…”

Carbon Dots: Bottom‐Up Syntheses, Properties, and Light‐Harvesting Applications

“…[66] acid) composite with excellent activityi nH 2 evolution. [61] The functional groups of CDsw ere reduced from the carboxylic and carbonyl groups to hydroxyl groups to enhance the electron transfer and electrostatic adsorptiono fP ta nionic species. The surface-reduced CDsa bsorbed solar light and generated electrons,w hich transferred to Pt clusters, thus yielding 681 mmol g À1 h À1 of H 2 evolution.O ng et al prepared ag -C 3 N 4 / CD (from l-ascorbic acid) composite by meanso fi ns itu carbonization on the surfaceo fg -C 3 N 4 ,a ss hown in Figure 9a.…”

“…Xu et al. synthesized a Pt/CD (from citric acid) composite with excellent activity in H 2 evolution . The functional groups of CDs were reduced from the carboxylic and carbonyl groups to hydroxyl groups to enhance the electron transfer and electrostatic adsorption of Pt anionic species.…”

Enriching Hot Electrons via NIR‐Photon‐Excited Plasmon in WS2@Cu Hybrids for Full‐Spectrum Solar Hydrogen Evolution

“…To warrant serious practical interest, the solar‐to‐hydrogen (STH) conversion efficiency can be the most critical concern, which still suffers from some typical constraints including inadequate solar light utilization and severe charge‐carrier recombination. Many studies have focused on expanding the response range of semiconductor photocatalysts to the solar light spectrum for the enhanced STH efficiency . However, the near‐infrared (NIR) light that contains approximately 45% of solar light energy becomes an awkward portion because its photonic energy may be too low to meet directly the basic thermodynamics of water redox reaction .…”