Determining Plasmonic Hot Electrons and Photothermal Effects during H₂ Evolution with TiN–Pt Nanohybrids

Abstract

Hydrogen storage in chemical compounds is a promising strategy to enable lightweight, high-density, and safe hydrogen technologies. However, the hydrogen release rate from these chemicals is limited by the intrinsic catalytic activity of metal catalysts, which can be enhanced by light irradiation. Here, nanohybrids including a core of plasmonic TiN and multiple Pt nanocrystal catalytic centers are assembled and show, under resonant conditions at 700 nm, hot electron-driven hydrogen evolution from ammonia borane at an apparent quantum yield of 120%. It is also demonstrated that solar irradiation enhances the activity of TiN–Pt nanohybrids by one order of magnitude through two synergistic mechanisms: hot electrons and collective-heating contributions. Using the microscopic calculation of the photo-induced temperature around a single nanocrystal, it is revealed that the collective plasmonic heating regime dominates the macroscopic temperature distribution in the system. The presented data show that plasmonic hot electrons and photothermal heating can be used in synergy to trigger hydrogen release from ammonia borane on demand, providing a general strategy for greatly enhancing the activity of metal catalysts in the dark.

Fundamentals and applications of photo-thermal catalysis

“…An alternative process to generate hydrogen proposed in this current year by Dai and by Naldoni is the photo-thermally enhanced hydrolysis of ammonia borane, whose hydrogen content is 19.6%. [266][267][268] Wu et al prepared a series of urchin-like sodium titanate microspheres supported on the reduced graphene oxide (RGO/Na 2 Ti 3 O 7 ) photo-thermal catalyst with different graphene oxide content (0, 33, 50, 60, 66 wt%). 266 Particularly, they focused on the challenging aspect of synthesis optimization, elucidating the role of graphene oxide sheets in the growth mechanism of Na 2 Ti 3 O 7 microspheres.…”

Well-defined Cu2O photocatalysts for solar fuels and chemicals

“…To evaluate it, the experiments must be carried out under different monochromatic light irradiation. 125 Photon ux must be always reported during the demonstration of experimental procedures.…”

“…Apart from the Z-scheme mechanism, the construction of hybrid 'antenna-reactor' photocatalysts also attracted huge attraction due to their enhanced photocatalytic performance compared to their individual components. 125,213,214,223 In this system, generally plasmonic materials (such as Au, Ag, Cu, TiN, and Al) act as an 'antenna', which mainly absorbs the light and generates hot electrons (and eventually heat). These hot electrons are then transferred to the 'reactor' site (usually formed by transition metals such as Pt, Pd, Rh, Ru), which is mostly responsible for performing the photocatalytic reaction.…”

Synthesis and Characterization of Zinc Peroxide Nanoparticles for the Photodegradation of Nitrobenzene Assisted by UV-Light

“…When an electron/hole pair is generated at a surface, several events can occur. They can recombine, irradiating the input energy as heat, cause collective plasmonic heating, produce hot electrons [23], enter in a metastable state or react with electron donors and acceptors adsorbed or near the surface of the particle [48][49][50]. These two last reasons are the main cause of the decrease in NB concentration.…”

“…A technique involving a semiconductor photocatalyst and a contaminant has been used for the purification of air and water, which consists of the production of an electron/hole pair after illuminating the semiconductor with energetic enough photons [22]. It has also been seen that irradiation of a nano photocatalyst activity is enhanced through two synergistic mechanisms: the effect of plasmonic hot electrons and photothermal collective heating [23]. Titanium dioxide, TiO 2 , is the most common semiconductor photocatalyst and has been used for the degradation of energetic compounds like NB when exposed to ultraviolet irradiation thanks to their large bandgap (e.g., 3.0-3.2 eV) [24][25][26].…”