Researchers at the University of Electronic Science and Technology of China (UESTC) have announced a transformative breakthrough in the field of solar-driven carbon dioxide (CO₂) conversion. Their innovative research, focused on engineering strain into metal-halide perovskite nanowires, has resulted in a substantial enhancement in photocatalytic efficiency, delivering a remarkable fivefold increase in carbon monoxide (CO) production rates compared to traditional, unstrained catalysts. This advancement opens new frontiers in the quest for sustainable solar fuels, leveraging precise lattice-level control to optimize catalyst performance.
At the heart of this breakthrough is the concept of strain engineering, a sophisticated approach involving the deliberate manipulation of internal lattice tension within the photocatalytic material. The UESTC research team fabricated cesium lead bromide (CsPbBr₃) perovskite nanowires with varying degrees of biaxial tensile strain, ranging from zero strain to just under one percent. This was achieved through a controlled synthesis method that induced an internal lattice mismatch by introducing a secondary phase of cesium lead pentabromide (CsPb₂Br₅), allowing for strain tuning at the nanoscale with unprecedented precision.
One of the primary obstacles in photocatalytic CO₂ reduction has been the rapid recombination of photogenerated electrons and holes, which occurs before these charge carriers can participate effectively in chemical reactions. The introduction of tensile strain in these perovskite nanowires plays a crucial role in mitigating this challenge. By precisely adjusting the strain, the team was able to modulate the lattice properties such that charge recombination was hindered, thereby dramatically improving photocatalytic efficiency.
The most significant performance was observed in nanowires subjected to a tensile strain of approximately 0.47%, identified as the NW-LS sample. These strained nanowires exhibited a CO production rate of about 150.2 micromoles per gram per hour (μmol g⁻¹ h⁻¹), outperforming their unstrained counterparts by a factor of five while maintaining perfect selectivity for CO over other potential reduction products. Additionally, the catalysts demonstrated remarkable stability, retaining their activity over extended operational periods, an essential criterion for practical applications.
To unravel the mechanisms underpinning this improvement, the researchers employed a suite of advanced spectroscopic and theoretical techniques, including femtosecond transient absorption spectroscopy, in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and state-of-the-art density functional theory (DFT) simulations. These methods provided insights into how tensile strain influences the electronic structure and charge dynamics within the catalyst at both macroscopic and atomic scales.
Their findings reveal two fundamental effects induced by tensile strain that collectively enhance photocatalytic CO₂ conversion efficiency. First, strain amplifies lattice distortions associated with charge carriers, promoting the formation and stabilization of polarons—quasiparticles resulting from the coupling of electrons or holes with local lattice deformations. This regulated polaron behavior raises the energy barriers for electron-hole recombination, effectively elongating charge carrier lifetimes. Quantitatively, the decay lifetime of photogenerated charges increased dramatically from 672 picoseconds in unstrained samples to 2.85 nanoseconds in optimally strained nanowires, highlighting substantially enhanced charge separation.
Second, the strain engineering subtly shifts the electronic structure at the catalyst surface, particularly raising the energy level of the lead (Pb) atom’s p-orbitals. This shift improves the interaction between the catalyst surface and critical reaction intermediates, notably the *COOH species which governs the rate-determining step in CO₂ reduction to CO. In-situ spectroscopic observations confirmed a more rapid accumulation of this intermediate on strained catalyst surfaces, correlating with the lowered thermodynamic barriers predicted by theoretical calculations.
The nuanced interplay between mechanical deformation and electronic modification elucidated in this work underscores the power of strain engineering as more than a fine-tuning tool; it emerges as a fundamental strategy for controlling charge dynamics and surface chemistry in soft lattice materials like metal-halide perovskites. Jianping Sheng, the study’s corresponding author, emphasized that their approach transcends conventional electronic property adjustments, delving into the manipulation of polaron behaviors that critically dictate photocatalytic activity.
Importantly, the researchers demonstrated that the strained CsPbBr₃ nanowires not only surpass existing state-of-the-art perovskite-based photocatalysts in efficiency but also set a new benchmark for stability and selectivity. This accomplishment signifies an essential step toward scalable, efficient solar fuel production technologies that could mitigate greenhouse gas emissions by effectively converting CO₂ into valuable chemical fuels under solar illumination.
This research reflects the growing trend of integrating mechanical engineering principles within materials science to unlock novel functionalities and performance enhancements. It offers profound implications for the design of next-generation photocatalytic and electrocatalytic systems, where controlling lattice strain and polaron dynamics could become standard practices for achieving superior catalytic behaviors.
Given the escalating urgency for renewable energy solutions, the UESTC team’s work represents a pivotal contribution with broad applicability. It bridges fundamental scientific insights and practical technology development, emphasizing how meticulous atomic-scale engineering can deliver macro-scale environmental benefits. As global efforts to combat climate change intensify, innovations like this position metal-halide perovskites and related materials at the forefront of sustainable energy research.
Beyond environmental impact, this approach could inspire exploration into other catalytic processes where charge recombination limits efficiency, including water splitting and organic synthesis. The methodology combining experimental strain control, ultrafast spectroscopy, and computational modeling sets a comprehensive framework for future investigations.
The University of Electronic Science and Technology of China continues to solidify its role as a leader in advanced materials research, with this study conducted under the auspices of its School of Resources and Environment and Institute of Fundamental and Frontier Sciences. Their cross-disciplinary expertise in energy materials, environmental catalysis, and pollution control underscores the strategic importance of this scientific achievement.
As the global scientific community seeks sustainable, efficient routes for solar energy conversion, strain engineering of perovskite nanostructures emerges as a versatile and powerful paradigm. The UESTC research not only deepens our understanding of perovskite photocatalysts but also sets a vibrant direction for innovation that may soon translate into real-world technologies, contributing concretely to clean energy transitions worldwide.
Subject of Research: Solar-driven CO₂ conversion using strain-engineered metal-halide perovskite photocatalysts
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Web References: http://dx.doi.org/10.1016/j.scib.2025.06.008
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Image Credits: ©Science China Press
Keywords
Strain engineering, perovskite nanowires, photocatalysis, CO₂ reduction, carbon monoxide production, polaron regulation, lattice distortion, femtosecond transient absorption, in-situ infrared spectroscopy, density functional theory, charge recombination, metal-halide perovskites
