A current challenge in green hydrogen production is enhancing the efficiency of the alkaline hydrogen evolution reaction (HER), where the kinetics are notably hampered by the sluggish dissociation of water (H2O). Statistical insights reveal that over 95% of current hydrogen production processes are rooted in fossil fuels, underscoring the critical need to develop efficient electrocatalytic processes that utilize renewable energy sources. An innovative approach to addressing this issue involves manipulating the micro-environment at the interface of catalysts to improve water molecule orientation and reaction kinetics.
The potential application of lattice strain to influence water orientation at the interface of a transition metal phosphide (TMP) catalyst adds a compelling dimension to this approach. TMPs, such as FeP, are emerging as promising candidates for inexpensive hydrogen catalysts, demonstrating competitive catalytic activity for alkaline HER. Unlike precious metals like platinum, whose scarcity poses economic barriers, TMPs offer a more sustainable and cost-effective alternative.
Market analysis underscores the shift towards such alternatives, with the global market for hydrogen projected to grow at a compound annual growth rate (CAGR) of over 9% by 2030. However, formidable barriers persist in optimizing the performance of non-noble metals in HER processes.
Lattice strain in TMPs can modify the electronic structure and, thus, catalytic performance by influencing the orientation of H2O at the interface. The applied strain can alter the Fe–O bond distance, impacting the dissociation process of water. In FeP, for example, tensile strain causes a shift from an H-down to an O-down configuration, which is theoretically shown to decrease the Fe–O bond length — an effect demonstrated using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations.
Such strain-induced reorientation offers an untapped potential to enhance the kinetics of alkaline HER and accelerate hydrogen production rates. Market projections and existing experimental validations reveal that such strain manipulations could indeed prove significant in increasing TMPs’ efficiency in catalysis. The incorporation of strain manipulation into catalyst design could lead to a reduction in the H2O dissociation energy barrier, improving proton supply and optimizing hydrogen adsorption energy.
This strategy is bolstered by data showing TMPs’ promising activity for water splitting. Current TMP research highlights transition metals’ dual role in water decomposition and H2 desorption — essential steps in HER. By tuning strain, researchers can potentially enhance electron transfer properties and active site availability, bridging the gap between theoretical performance and practical application.
To harness the potential of strain-induced modifications, it’s crucial to deepen our understanding of the mechanistic pathways involved in strain and molecular reorientation. Furthermore, current studies focus on elucidating these effects in simulated environments. The incorporation of real-world conditions in future studies will be essential. The evidence suggests that aligning catalyst development with the fluctuating dynamics of lattice strain could redefine the efficiency standards of TMPs in catalytic hydrogen production.
Future success hinges on the ability of researchers to integrate these findings into scalable solutions that meet industry demands. As efforts continue, the role of lattice strain in optimizing water orientation not only reveals a nuanced approach to catalysis but also opens new avenues for sustainable hydrogen production.
