LaFeO3 Modified with Ni for Hydrogen Evolution via Photocatalytic Glucose Reforming in Liquid Phase

Giuseppina Iervolino,María C Hidalgo,Diana Sannino,Felipe Puga,Vincenzo Vaiano,Josè Antonio Navío

doi:10.3390/catal11121558

Abstract

In this work, the optimization of Ni amount on LaFeO3 photocatalyst was studied in the photocatalytic molecular hydrogen production from glucose aqueous solution under UV light irradiation. LaFeO3 was synthesized via solution combustion synthesis and different amount of Ni were dispersed on LaFeO3 surface through deposition method in aqueous solution and using NaBH4 as reducing agent. The prepared samples were characterized with different techniques: Raman spectroscopy, UltraViolet-Visible Diffuse Reflectance Spettroscopy (UV–Vis-DRS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), X-ray Fluorescence (XRF), Transmission Electron microscopy (TEM), and Scanning Electron microscopy (SEM) analyses. For all the investigated photocatalysts, the presence of Ni on perovskite surface resulted in a better activity compared to pure LaFeO3. In particular, it is possible to identify an optimal amount of Ni for which it is possible to obtain the best hydrogen production. Specifically, the results showed that the optimal Ni amount was equal to nominal 0.12 wt% (0.12Ni/LaFeO3), for which the photocatalytic H2 production was equal to 2574 μmol/L after 4 h of UV irradiation. The influence of different of photocatalyst dosage and initial glucose concentration was also evaluated. The results of the optimization of operating parameters indicated that the highest molecular hydrogen production was achieved on 0.12Ni/LaFeO3 sample with 1.5 g/L of catalyst dosage and 1000 ppm initial glucose concentration. To determine the reactive species that play the most significant role in the photocatalytic hydrogen production, photocatalytic tests in the presence of different radical scavengers were performed. The results showed that •OH radical plays a significant role in the photocatalytic conversion of glucose in H2. Moreover, photocatalytic tests carried out with D2O instead of H2O evidenced the role of water molecules in the photocatalytic production of molecular hydrogen in glucose aqueous solution.

Highlights

For several decades, the use of hydrogen as an energy vector and not just as a raw material for the process industry was considered as a possible key element for the decarbonization of energy systems
In this work, the optimization of Ni amount on LaFeO3 photocatalyst was studied in the photocatalytic molecular hydrogen production from glucose aqueous solution under UV light irradiation
LaFeO3 was synthesized via solution combustion synthesis and different amount of Ni were dispersed on LaFeO3 surface through deposition method in aqueous solution and using NaBH4 as reducing agent

Summary

Introduction

The use of hydrogen as an energy vector and not just as a raw material for the process industry was considered as a possible key element for the decarbonization of energy systems. Due to the depletion of not-renewable sources and the high amount of energy required, the production of molecular hydrogen through these two processes is unsustainable and uneconomical. Thanks to the development of innovative technologies, molecular hydrogen can be obtained from a widely diversified range of renewable energy sources, being able to support the development of resilient energy systems [1,2]. Some recent advances in molecular hydrogen production indicate that a possible route is to perform cycloalkanes [3] and alcohol dehydrogenation [4] as green and sustainable method, and to realize hydrolytic dehydrogenation of ammonia borane on reduced CoFe2O4 for the H2 evolution [5] or the hydrolysis of NaBH4 on ZIF-8 materials [6]

Objectives

Methods

Results