A review on g-C3N4-based photocatalysts

Furfural and 5-hydroxymethylfurfural stand out as bridges connecting biomass raw materials to the biorefinery industry. Their reductive transformations by hydroconversion are key routes toward a wide variety of chemicals and biofuels, and heterogeneous catalysis plays a central role in these reactions. The catalyst efficiency highly depends on the nature of metals, supports, and additives, on the catalyst preparation procedure, and obviously on reaction conditions to which catalyst and reactants are exposed: solvent, pressure, and temperature. The present review focuses on the roles played by the catalyst at the molecular level in the hydroconversion of furfural and 5-hydroxymethylfurfural in the gas or liquid phases, including catalytic hydrogen transfer routes and electro/photoreduction, into oxygenates or hydrocarbons (e.g., furfuryl alcohol, 2,5-bis(hydroxymethyl)furan, cyclopentanone, 1,5-pentanediol, 2-methylfuran, 2,5-dimethylfuran, furan, furfuryl ethers, etc.). The mechanism of adsorption of the ...

How Catalysts and Experimental Conditions Determine the Selective Hydroconversion of Furfural and 5-Hydroxymethylfurfural.

Ultrathin dielectric gaps between metals can trap plasmonic optical modes with surprisingly low loss and with volumes below 1 nm3. We review the origin and subtle properties of these modes, and show how they can be well accounted for by simple models. Particularly important is the mixing between radiating antennas and confined nanogap modes, which is extremely sensitive to precise nanogeometry, right down to the single-atom level. Coupling nanogap plasmons to electronic and vibronic transitions yields a host of phenomena including single-molecule strong coupling and molecular optomechanics, opening access to atomic-scale chemistry and materials science, as well as quantum metamaterials. Ultimate low-energy devices such as robust bottom-up assembled single-atom switches are thus in prospect.

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Extreme nanophotonics from ultrathin metallic gaps

To achieve efficient photocatalytic air purification, we constructed an advanced semimetal–organic Bi spheres–g-C3N4 nanohybrid through the in-situ growth of Bi nanospheres on g-C3N4 nanosheets. This Bi–g-C3N4 compound exhibited an exceptionally high and stable visible-light photocatalytic performance for NO removal due to the surface plasmon resonance (SPR) endowed by Bi metal. The SPR property of Bi could conspicuously enhance the visible-light harvesting and the charge separation. The electromagnetic field distribution of Bi spheres involving SPR effect was simulated and reaches its maximum in close proximity to the Bi particle surface. When the Bi metal content was controlled at 25%, the corresponding Bi–g-C3N4 displayed outstanding photocatalytic capability and transcended those of other visible-light photocatalysts. The Bi–g-C3N4 exhibited a high structural stability under repeated photocatalytic runs. A new visible-light-induced SPR-based photocatalysis mechanism with Bi–g-C3N4 was proposed on the ...

An Advanced Semimetal–Organic Bi Spheres–g-C3N4 Nanohybrid with SPR-Enhanced Visible-Light Photocatalytic Performance for NO Purification

A controllable vacuum-diffusion method for gradual phosphidation of carbon coated metallic Co nanoparticles into Co/CoP Janus nanoparticles is reported. Janus Co/CoP nanoparticles, as typical Mott–Schottky electrocatalysts, exhibit excellent hydrogen evolution reaction and oxygen evolution reaction performance in various electrolytes across wide pH range along with high durability. The Mott–Schottky Co/CoP catalyst can work as bifunctional electrode materials for overall water splitting in wide pH range and can achieve a current density of 10 mA cm−2 in neutral electrolyte at only 1.51 V.

Janus Co/CoP Nanoparticles as Efficient Mott–Schottky Electrocatalysts for Overall Water Splitting in Wide pH Range

Highly Efficient Dehydrogenation of Formic Acid over a Palladium‐Nanoparticle‐Based Mott–Schottky Photocatalyst

A magnetically recyclable carbon nitride supported Au–Co nanoparticles (Au–Co@CN) displayed exceedingly high photocatalytic activity for hydrolysis of aqueous ammonia borane (NH3BH3, AB) solution. Combined with a synergetic effect between Au and Co nanoparticles, the Motty–Schottky effect at the metal–semiconductor interface remarkably facilitated the catalytic performance of the Au–Co@CN catalyst on the hydrolysis of AB. The TOF value of Au–Co@CN catalyst is 2897 mol H2 mol–1 metal h–1 at 298 K under visible light irradiation, which is more than 3 times higher than that of the benchmarked catalyst, PVP-stabilized Au@Co nanoparticles.

Multifunctional Au–Co@CN Nanocatalyst for Highly Efficient Hydrolysis of Ammonia Borane

We demonstrate, experimentally and theoretically, that the photon emission from gold nanorods can be viewed as a Purcell effect enhanced radiative recombination of hot carriers. By correlating the single-particle photoluminescence spectra and quantum yields of gold nanorods measured for five different excitation wavelengths and varied excitation powers, we illustrate the effects of hot carrier distributions evolving through interband and intraband transitions and the photonic density of states on the nanorod photoluminescence. Our model, using only one fixed input parameter, describes quantitatively both emission from interband recombination and the main photoluminescence peak coinciding with the longitudinal surface plasmon resonance.

Photoluminescence of Gold Nanorods: Purcell Effect Enhanced Emission from Hot Carriers.

Removing effects of sample heterogeneity through single-molecule and single-particle techniques has advanced many fields. While background free luminescence and scattering spectroscopy is widely used, recording the absorption spectrum only is rather difficult. Here we present an approach capable of recording pure absorption spectra of individual nanostructures. We demonstrate the implementation of single-particle absorption spectroscopy on strongly scattering plasmonic nanoparticles by combining photothermal microscopy with a supercontinuum laser and an innovative calibration procedure that accounts for chromatic aberrations and wavelength-dependent excitation powers. Comparison of the absorption spectra to the scattering spectra of the same individual gold nanoparticles reveals the blueshift of the absorption spectra, as predicted by Mie theory but previously not detectable in extinction measurements that measure the sum of absorption and scattering. By covering a wavelength range of 300 nm, we are furth...

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Single-Particle Absorption Spectroscopy by Photothermal Contrast

Room-temperature transfer hydrogenation and fast separation of unsaturated compounds over heterogeneous catalysts in an aqueous solution of formic acid

Yi-Yu Cai

Papers

Highly Efficient Dehydrogenation of Formic Acid over a Palladium‐Nanoparticle‐Based Mott–Schottky Photocatalyst

Multifunctional Au–Co@CN Nanocatalyst for Highly Efficient Hydrolysis of Ammonia Borane

Photoluminescence of Gold Nanorods: Purcell Effect Enhanced Emission from Hot Carriers.

Single-Particle Absorption Spectroscopy by Photothermal Contrast

Room-temperature transfer hydrogenation and fast separation of unsaturated compounds over heterogeneous catalysts in an aqueous solution of formic acid