With the escalating global energy crisis and environmental pollution, the search for renewable and clean energy sources has become a common challenge for humanity. Solar energy, being an ideal renewable resource, is abundant and inexhaustible. However, due to objective factors such as weather, geography, and day-night cycles, it has the disadvantages of intermittency and variability.
Photovoltaic electrocatalytic water splitting technology not only overcomes the drawbacks of the intermittent and fluctuating nature of solar energy but also transforms solar energy into a storable, transportable, and high-energy-density clean energy source—hydrogen. This technology provides a research direction for future solar energy conversion, offering a solution to the issues of intermittency and variability associated with solar energy[1].
Photovoltaic electrocatalytic water splitting uses photovoltaic devices to convert solar energy into electricity, which is then used by the catalyst to catalyze the decomposition of water into hydrogen and oxygen.
1. Renewable Energy: Photovoltaic electrocatalytic water splitting technology uses solar energy as a source, with characteristics such as renewability and non-pollution.
2. Clean Energy: The combustion product of hydrogen from water splitting is only water, resulting in no greenhouse gas emissions, making it a clean energy source.
3. Hydrogen as Fuel: Hydrogen can serve as a fuel, providing a new solution for energy diversification when combined with other renewable energy sources.
4. Wide Application: Photovoltaic electrocatalytic water splitting technology can be applied in transportation, industry, households, etc., providing possibilities for energy transition.
Photovoltaic electrocatalytic water splitting is a technology with enormous potential, but it still faces difficulties and challenges in practical applications, mainly concentrated in the following aspects:
1. Efficiency Issue: Photovoltaic electrocatalytic water splitting involves converting solar energy into electricity, which is then used for catalyzing the water splitting process. There are energy losses in this process, and improving overall efficiency is a key focus.
2. Catalyst Selection and Design: Finding efficient, stable, and low-cost catalysts is crucial for photovoltaic electrocatalytic water splitting technology. The catalysts need to efficiently catalyze water decomposition, operate for a long time without deactivation, and not be affected by issues such as catalyst poisoning or corrosion.
3. System Integration: Efficiently integrating photovoltaic devices, electrolysis cells, catalysts, and other components to reduce system costs is a challenge that needs to be addressed.
4. Stability and Durability: In photovoltaic electrocatalytic water splitting, instruments and materials face constant exposure to high-energy light, ongoing chemical reactions in the electrolyte, and long-term use. Therefore, improving the stability and durability of photovoltaic electrocatalytic water splitting systems is essential to ensure their reliability in practical applications.
5. Scaling Issue: Scaling up photovoltaic electrocatalytic water splitting technology from laboratory scale to industrial production remains a significant challenge. Establishing large-scale production and scalable basic platforms and addressing stability and controllability issues in large-scale production are necessary.
Methods to Improve Electrolysis Efficiency[2]
Photovoltaic electrocatalytic water splitting technology has vast prospects for future development. The main methods to improve photovoltaic electrocatalytic water splitting are as follows:
1. New Catalysts: Researchers will continue to explore more efficient and stable catalysts that can work under various conditions and remain effective over long periods.
2. System Integration: Integration of different components and modules, such as choosing cost-effective ion exchange membranes, optimizing photovoltaic cells, improving battery life and capacity, and developing more valuable electrodes.
3. Increase Energy Utilization Efficiency: For example, by designing photovoltaic panels that can track the sun's position to be in the optimal sunlight direction continually and optimizing electrolysis cell design to enhance the efficiency of the reaction.
4. Hybrid Power Systems: Ensuring uninterrupted operation by integrating multiple power sources or combining two or more configurations for maximum effect to improve system efficiency.
5. Hybrid Power: Expanding the energy sources for photovoltaic water electrolysis to include wind energy, geothermal energy, etc., and connecting or combining other devices in parallel or series to extend applications to electricity, heat, and cooling demands, expanding possibilities in modern zero-carbon emission energy.
Future Trends in Photovoltaic Electrocatalysis[2]
To assist researchers in exploring the coupling of photovoltaic power generation and electrocatalytic preparation of green fuels, Perfect Light Technology has introduced an outdoor experimental system platform—PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System.
The PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System consists of photovoltaic equipment, customized catalytic reactors, circulation systems, monitoring and control systems, support frames, collection and emission systems, and accompanying equipment.
The catalytic reactor is divided into a pure electrocatalytic reactor and a photoelectrocatalytic reactor with a light window. It aims to build a photovoltaic + photoelectrochemical (electrochemical) hydrogen production reaction device, realizing photoelectrochemical (electrochemical) hydrogen and oxygen production under acidic and alkaline conditions. The catalytic hydrogen production efficiency reaches the 10 L/h level, meeting outdoor usage requirements.
Real-time tracking system, maximizing solar light utilization
PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System is equipped with photovoltaic panels with irradiance detectors, measuring real-time photovoltaic irradiance in the environment. Based on irradiance, the inclination angle of the photovoltaic panel is adjusted to maximize light energy utilization.
Plate Reactor Structure, Improving Electrocatalytic Reaction Efficiency
PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System configures the reactor as a plate-type reaction structure, significantly increasing the surface area of the electrode catalytic material compared to the same volume pot-type electrolytic cell, allowing the catalyst to make more effective contact with the reactants;
The thin-layer structure reduces the thickness of the solution layer, reducing uneven distribution of reactants caused by low diffusion rates, lowering the occurrence of side reactions, and improving product selectivity;
The flow system can enhance the transfer rates of electrons and protons during the catalytic process, improving the reaction rate.
Flexible Reactor Design, Meeting Reactions at Different Scales and Conditions
PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System's plate-type structure can be rapidly expanded and optimized as needed. Reactor sizes can be selected as 5×5, 10×10, 15×15, 20×20, 25×25 cm², or customized to meet different scale and efficiency requirements under various conditions.
It can also customize a photoelectrochemical reactor with a light window, with a light-receiving area of up to 625 cm² (25 cm×25 cm). The catalyst's light-receiving area is larger during the reaction, and the reactor's angle can be adjusted in real-time to improve the catalyst's light efficiency.
Multi-functional Real-time Monitoring System, Ensuring Safe and Controllable Large-scale Hydrogen Production
PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System can real-time monitor parameters such as irradiance intensity, voltage, current, hydrogen production, pH value, and temperature. This allows adjusting reaction conditions and optimizing reaction results.
Graded Circulating Power System, Ensuring Efficient Reaction and Timely Separation of Products
PLR-PVERS Series Solar Photovoltaic Electrochemical Catalysis Reaction System uses a miniature pump to drive liquid flow, allowing the reaction solution to fully contact the electrode. Simultaneously, a gas pump is configured at the product end to promptly separate and collect the gaseous products generated during the reaction, effectively improving circulation efficiency and reaction efficiency.
References
[1] Chen Jing, Dong Shujie, and Zhou Hongjun. Research progress on hydrogen production through solar photovoltaic effect [J]. Coal Chemical Industry, 2022, 50(03):79-85.
[2] Makhsoos A, Kandidayeni M, Pollet B G, et al. A perspective on increasing the efficiency of proton exchange membrane water electrolyzers—a review [J]. International Journal of Hydrogen Energy, 2023.
