Understanding hydrogen adsorption on metal nanoparticles is key to improving catalysts for hydrogen energy applications. Using density functional theory, we examine hydrogen adsorption on Pt147, Pt146Ni1, Pt134Ni13, and Pt92Ni55 to assess how Ni content and distribution affect reactivity. We calculate adsorption energies and H-Pt bond lengths at ten surface sites per cluster. Results show that Ni composition strongly influences preferred adsorption sites and strengths. Multiple hydrogen adsorption reveals that Pt147 and Pt146Ni1 clusters exhibit nearly identical adsorption energetics and maintain structural stability. In contrast, higher Ni content in Pt134Ni13 and especially Pt92Ni55 weakens hydrogen binding and induces greater lattice distortion, reflecting a trade-off between adsorption strength and structural stability. Analysis of local atomic pressure distributions highlights a strong correlation between surface tensile pressure and hydrogen adsorption behaviour. Clusters with pronounced surface tensile pressure exhibit more favourable adsorption energetics. These insights support the strategic design of bimetallic nanoalloys for efficient hydrogen catalysis.