Operational Conditions Affecting Hydrogen Production by the Photoreforming of Organic Compounds using Titania Nanoparticles with Gold

Abstract

Several factors affect photocatalytic hydrogen productivity from the photoreforming of organic compounds, which makes it difficult to optimize operational conditions in photoreactors. To prioritize these factors, we focused on the quantification of the effect of five of them on hydrogen production. Photocatalytic experiments were performed on 67 mL batch photoreactors under UV‐LED lamps (λ=375 nm) using a suspension of TiO2–Au nanoparticles synthesized by a sol–gel approach. The analyzed factors were: (A) presence of Au as a cocatalyst, (B) type of alcohol as the electron donor, (C) intensity of UV light, (D) electron donor concentration, and (E) nanoparticle concentration. A main and interaction effects analysis is presented with reduced fixed effect models for three responses: total hydrogen generation, catalyst productivity, and electron donor productivity. The presence of Au as a cocatalyst (A), the intensity of UV light (C), and their interaction (AC) were the factors with the highest effect. The best configuration allowed us to reach a catalyst productivity of 2925 μmolnormalH2 g−1 h−1.

Carbon‐Coated Cu nanoparticles as a Cocatalyst of g‐C3N4 for Enhanced Photocatalytic H2 Evolution Activity under Visible‐Light Irradiation

“…[15,16] Many studies have proved that the hydrogen production efficiency of g-C 3 N 4 can be promoted effectively by adding precious metals such as Pt, Au, or Ag. [17][18][19][20] In terms of economic and practical production, research has been done on the use of transition metals (such as Fe, Co, Ni, and Cu) or corresponding oxides as cocatalysts. [21][22][23][24] It has been proposed that the modification of g-C 3 N 4 by Cu nanoparticles (Cu/g-C 3 N 4 ) improves the photocatalytic efficiency of g-C 3 N 4 .…”

Operational Conditions Affecting Formaldehyde and Formic Acid Formation as By‐Products of Hydrogen Production via Photo‐Reforming of Methanol Using Nanoparticles of TiO2

“…Photocatalytic hydrogen production process is a way to store solar energy in chemical energy using nano‐sized semiconductors . Titanium dioxide is the most widely used semiconductor for photocatalytic applications because it is stable, noncorrosive, harmless, abundant, inexpensive, and able to generate the water splitting reaction and photo‐reforming of several organic compounds …”

“…Many studies use methanol as a sacrificial agent because it captures the positive charge carriers more rapidly than other alcohols;, it has a high hydrogen/carbon ratio and it can be obtained from biomass ,,…”

“…Particle size and loading amount of co‐catalysts,,, type and concentration of sacrificial agents,,,, have been studied too. Less studied but equally relevant for bigger scale applications are the effects of light intensity and photocatalyst concentration because of the possible screening effect on the bulk of the reaction media …”

“…In this context, this work studies the joint effect of four relevant factors: (A) presence of gold as co‐catalyst, (B) intensity of light, (C) concentration of methanol and (D) concentration of nanoparticles. A previous work deeply analyzed their effect on the hydrogen production using low concentrations of nanoparticles, since a gap exists in the knowledge about photocatalysis using concentrations of nanoparticles below 0.1 g⋅L −1 . Along the same lines, this present work explores their combined effect on the formation of formaldehyde and formic acid as potential valuable by‐products of the hydrogen production process via photoreforming of methanol, in a low range concentration of nanoparticles.…”