Black Gold-Based “Antenna–Reactor” To Activate Non-Plasmonic Nickel: Photocatalytic Hydrodechlorination and Hydrogenation Reactions

Abstract

Activation of organic chlorides is a challenging reaction due to their chemical inertness, while hydrogenation of alkene and alkynes faces poor selectivity. In this work, we have demonstrated the use of nickel-loaded black gold (black Au−Ni) that absorbs broadband light from visible to near-infrared of the sunlight due to plasmonic coupling between Au NPs, for photocatalytic hydrodechlorination and propene and acetylene hydrogenation reactions. Hot carriers, the polarizing electric field, and the photothermal effect generated in these catalysts enabled photocatalytic bond activation of these two challenging reactions using visible light at lower temperatures and atmospheric pressure. The black Au−Ni catalyst showed a multifold increase in its activity as compared to black Au. The plasmon-assisted reaction mechanism of hydrodechlorination was supported by intensity-dependent catalysis, kinetic isotope effect (KIE), competitive C−Cl bond activation with one-electron ferricyanide reduction, finite-difference time-domain (FDTD) simulations, and quantum chemical studies. Cluster model-based density functional theory studies show that the reactions have substantial barriers, which were bypassed via an excited state accessed through plasmonic excitations. FDTD studies indicate substantial enhancement of the electric field at the hotspots, iron reduction competed for hot carriers when run in conjunction with C−Cl bond activation, KIE was marginally higher in light as compared to the dark, and the catalyst showed power-dependent activity. These observations indicated the hot carrier involvement in the hydrodechlorination reactions in addition to the photothermal effect.

Engineering Ultrathin Alloy Shell in Au@AuPd Core‐Shell Nanoparticles for Efficient Plasmon‐Driven Photocatalysis

“…(Figure S10, Supporting Information). [66][67][68][69] Additionally, the reactions were conducted using well-separated NPs on the support to prevent heat accumulation, with precise temperature control and continuous stirring. Since we also employed the Au NPs of 5.5 ± 0.6 nm, the local heating effect is expected to be negligible, [61,[70][71][72] and the majority of the excited plasmon energy can be effectively utilized through light absorption (i.e., sp-sp intraband transition), primarily decaying via nonradiative electron-hole pair generation.…”

Plasmon–Exciton Coupling-Assisted Efficient Overall Water Splitting in Alkaline Medium Using a Plexcitonic NiO/Ni Foam Catalyst

“…The HER performance of the Au/NiO/Ni foam catalyst is significantly higher than that of the MoS 2 /NiO/Ni foam catalyst in the presence of white light irradiation (Figure b), reversing the trend observed without light irradiation (Figure a). This observation is important, as the plasmonic nanometals-incorporated Ni particles (termed as plasmonic black gold) have recently been reported as efficient catalysts for various photocatalytic reactions due to plasmonic coupling with Ni particles. , Here, we observe that the alkaline HER overpotential for the MoS 2 /NiO/Ni foam is reduced from 222 mV (without light) to 193 mV at 50 mA cm –2 , while that for the Au/NiO/Ni foam is lowered from 235 mV (without light) to a significantly low value of 156 mV at 50 mA cm –2 under photoelectrocatalytic (with light irradiation) conditions.…”

Challenges and opportunities for the photo-(thermal) synthesis of ammonia

“…Another possibility is to use secondary light-absorbing elements, whereby a catalytically active metal is coupled with another material able to absorb light in a wider range and generate photo-carriers and/or heat. 163–165 Core–shell structures have also received great attention, as the idea is to mimic a nanoreactor, confining the heat in the core, increasing the temperature precisely where the active sites are located. 166 Still in this context, MOFs can also be used as sacrificial templates to obtain carbon-based materials featuring broadband light absorption in the visible and IR light ranges.…”