The pH level greatly influences the effectiveness of the electrocatalyst in the hydrogen evolution reaction (HER). Recent studies have raised concerns about the conventional theoretical approach to predicting the HER, which relies on hydrogen adsorption energy as the primary reaction descriptor. Specifically, a more complex phenomenological approach tailored to alkaline environments has challenged this traditional method. However, water adsorption energy, the activation energy required for water spilling, and hydroxyl adsorption energy are as important as hydrogen adsorption energy. In addition, layered transition metal dichalcogenides (TMDs) have arisen as a novel category of catalytic materials that offer several benefits compared to noble metal catalysts. These advantages include their natural occurrence, lower cost, and accessibility. Chapter 2 provides a concise overview of several descriptors, such as water adsorption energy, water dissociation barrier, and Gibbs free energy changes, related to the adsorption of hydrogen and hydroxyl groups. Examples of applications of these descriptors to determine the active site of materials and enhance the design of high-performance alkaline HER electrocatalysts are presented, emphasizing the hitherto overlooked significance of hydroxyl adsorption-free energy shifts. To advance Alkaline Water electrolysis (AWE) technology for sustainable hydrogen production, it will be crucial to integrate these characteristics with experimental data as research advances. In Chapter 3, we employ hydrogen (H) and hydroxyl (OH) adsorption Gibbs free energy changes as indicators to examine the catalytic HER efficiency of 1T' TMDs in an alkaline solution. Our findings indicate that the pure sulphides exhibited superior alkaline HER performance compared to their selenide equivalents. Nevertheless, the activities of all pure 1T' TMDs are insufficient to decompose to water. To enhance the performance of these materials, defect engineering methods were employed to develop TMD-based electrocatalysts for efficient HER activity. The DFT results indicate that the improvement of reactivities in TMD materials can be achieved by the introduction of individual S/Se vacancy defects. However, the rate-determining step is the desorption of OH species. The reactivity of active sites for optimal OH desorption can be regulated by doping defective MoS2 with late 3d transition metal (TM) atoms, particularly Cu, Ni, and Co. Consequently, the defective 1T' MoS2 doped with TM can greatly improve the performance of the alkaline HER. The results emphasize the prospects of defect engineering techniques in designing alkaline HER electrocatalysts based on TMD. In conclusion, three descriptors - water adsorption energy, Gibbs free energy for hydrogen adsorption, and Gibbs free energy for hydroxyl adsorption - have been identified as effective tools for the design of alkaline electrocatalysts. Defective engineering and modification technology can significantly enhance a catalyst's HER performance.