Synthesis, characterization, and process optimization of a solar-driven photocatalytic CO2 reduction reactor using a composite Ni-doped g-C3N4/UiO-66-XZ catalyst for sustainable fuel production

Project Abstract

The project presents a comprehensive study on the synthesis, characterization, and process optimization of a solar-driven photocatalytic reactor designed for CO2 reduction to sustainable fuels, employing a composite Ni-doped g-C3N4/UiO-66-XZ catalyst engineered to maximize light absorption, charge separation, and catalytic activity under visible light. The synthesis phase focuses on integrating graphitic carbon nitride (g-C3N4) doped with nickel to tune electronic structure and mid-gap states, with a robust UiO-66-XZ metal-organic framework support to provide high surface area, porosity, and favourable CO2 adsorption sites. A systematic optimization strategy is implemented to achieve uniform Ni incorporation, controlled crystallinity, and intimate interfacial contact between the semiconductor and MOF, verified through X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Fourier-transform infrared spectroscopy. Optical properties are probed by UV-Vis diffuse reflectance spectroscopy and photoluminescence measurements to assess bandgap engineering and charge-carrier lifetimes, while surface chemistry is characterized by X-ray photoelectron spectroscopy and CO2-adsorption isotherms. Photocatalytic activity tests under simulated solar irradiation quantify CO2 reduction pathways to CO, formate, methane, and higher hydrocarbons, with product distribution analyzed by gas chromatography-mass spectrometry and online FTIR. A kinetic model linking light absorption, charge transfer, and catalytic surface reactions is developed to elucidate rate-limiting steps and to predict reactor performance. The reactor design integrates a photothermal management scheme and a flow-through configuration to enhance CO2 contact, mass transfer, and photon utilization, coupled with a dynamic light intensity control strategy to maintain optimal reactor conditions under diurnal solar cycles. Process optimization employs response surface methodology and design of experiments to identify the effects of catalyst loading, co-catalyst concentration, reactor residence time, gas flow rate, humidity, and temperature on CO2 conversion efficiency, product selectivity, and energy return on energy invested (EROEI). Stability and recyclability studies examine catalyst aging, nickel leaching, MOF structural integrity, and fouling due to condensation or mineral deposits, with regeneration protocols evaluated. Techno-economic analysis and life-cycle assessment provide a framework for assessing scalability, potential environmental impacts, and carbon footprint reductions in comparison with conventional fossil fuel synthesis routes. The expected outcomes include a robust Ni-doped g-C3N4/UiO-66-XZ catalyst exhibiting enhanced visible-light activity, improved charge separation efficiency, and higher CO2 conversion rates toward value-added fuels, along with a validated reactor model capable of predicting performance under realistic solar spectra and fluctuating environmental conditions. The research advances the integration of advanced photocatalysts with scalable reactor concepts to deliver a cleaner, solar-driven pathway for CO2 valorization, contributing to sustainable fuel production and reducing greenhouse gas emissions.

Project Overview

What This Project Is About

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A straightforward study about using a special catalyst to turn carbon dioxide from the air into useful fuels, powered by sunlight. The project combines making a new catalyst material and testing how well a small reactor can use it to convert CO2 into fuels like methane or methanol.

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The Problem It Addresses

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CO2 levels are rising and wasteful energy use is common, so turning CO2 into fuels with sunlight could reduce emissions and create renewable energy sources. The challenge is to design a catalyst and reactor that work efficiently, are stable, and can operate with real sunlight.

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Objectives of the Project

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1. Develop a composite Ni-doped g-C3N4/UiO-66-XZ catalyst and check its ability to absorb light and promote CO2 conversion.
2. Build a small solar-driven reactor to test the catalyst under simulated sunlight.
3. Measure how much fuel is produced and how fast, under different conditions.
4. Study how catalyst composition affects efficiency and stability.
5. Propose process improvements to increase yield and durability.

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What You Will Do Step by Step

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1) Review basic literature on photocatalysis and CO2 reduction. 2) Synthesize the Ni-doped g-C3N4/UiO-66-XZ catalyst in the lab. 3) Characterize the material (structure, composition, light absorption). 4) Assemble a small solar-powered reactor and run experiments. 5) Collect data on gas and liquid products. 6) Analyze results to find best operating conditions. 7) Test catalyst stability over time. 8) Write a short report with findings and recommendations.

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Expected Outcome

Anticipated results are a catalyst that efficiently uses sunlight to convert CO2 into useful fuels, with clearer relationships between catalyst design and performance. The project should provide a feasible route toward more sustainable fuel production and show practical steps for scaling up.