Palladium and Proton Knight Shift in Palladium Hydride

Abstract

Abstract The nuclear magnetic resonance of 105 Pd has been observed in α‐PdH n for the first time. The resonant field was measured at 75°C as a function of hydrogen pressure p within the entire α phase region. A linear relationship between Knight shift and hydrogen concentration has been established by comparison with the p ( n ) absorption isotherm at 75°C. Moreover, it has been found that the 105 Pd Knight shift K and the susceptibility x of α‐PdH n are linearly related. From the K — X dependence a value of ‐(1.80 ± 014)% for the Knight shift in pure palladium metal at 75 °C and a value of ‐(1.49 ± 015)% for PdH 0.025 at 75 °C could be determined. This may be attributed to the decreasing 4d spin susceptibility within the α phase. The proton Knight shift in α‐PdH n was also studied at 75°C. Similarly to the 105 Pd Knight shift the 1 H Knight shift in α‐PdH n depends linearly on hydrogen concentration and susceptibility. Knight shifts between ‐(93 ± 8) ppm for PdH 0.014 and ‐(50 ± 5) ppm for PdH 0.035 relative to the bare proton have been obtained.