Eva Wolfe

Student: Eva Wolfe

Project: Green Synthesis of Nanostructured Photocatalysts for Solar Hydrogen Production

Poster: Horizontal (PDF) | Vertical (PDF)

Institution: Lehigh University

Major: Chemical and Biomolecular Engineering

Advisor: Steven McIntosh

Abstract

Society is facing global energy and climate crises, which have arisen from the inability of the finite fossil fuel source to support energy consumption and the increase in greenhouse gas emissions produced from burning fossil fuels. Hydrogen is a clean source of energy in comparison to fossil fuels and can be produced by using visible light to induce water-splitting photoreactions. Photocatalysts absorb photons, exciting electrons within the catalyst to a higher energy state, which creates holes where the electrons used to be. The electrons migrate to the material’s surface and induce the reduction of water to hydrogen gas. Cadmium sulfide has a band gap within the energy range of visible light and is frequently used as a photocatalyst. Photocatalysts can be paired with cocatalysts, such as nickel sulfide, to prevent fast electron-hole recombination rates, thus improving hydrogen production rates. However, scalable implementation of photocatalytic reactions is still limited by reaction rates and photocatalyst instability. The literature suggests that synthesis of photocatalysts in zeolites (microporous crystalline aluminosilicate materials) can further prevent fast electron-hole recombination and promote increased contact between the photocatalyst and cocatalyst, thus improving reaction rates. The literature also suggests that the zeolite pore structure can protect photocatalysts from corrosion. In this work, we synthesize and characterize cadmium sulfide photocatalysts and nickel sulfide cocatalysts inside the pores of sodium-exchanged zeolite Y (CdS/NiS Na-Y), using ion exchange techniques. Future directions for this work include testing hydrogen production rates and photocatalyst stability using CdS/NiS Na-Y.