Effect of Pd4Cr6@NH2-Cr-MOF catalyst components on formic acid dehydrogenation

The catalytic performance of amino-anchored Pd-Cr nanoparticles on a Cr-based metal-organic framework (Pd4Cr6@NH2-Cr-MOF, specifically, where Cr-MOF denotes the chromium-based metal-organic framework MIL-101(Cr)) was evaluated through comparative experiments and characterization. Results show that neither pristine nor aminated Cr-MOF facilitates H2 evolution from formic acid, whereas both Pd and Cr nanoparticles exhibit measurable activity. Pd nanoparticles achieved peak and average H2 generation rates of 1.4 and 0.6 mL/min, roughly double those of Cr nanoparticles (0.8 and 0.3 mL/min). Remarkably, the Pd4Cr6@NH2-Cr-MOF composite attained dramatically enhanced rates of 86 mL/min (peak) and 15 mL/min (average), corresponding to a 25-fold activity improvement over monometallic Pd. This enhancement stems from: (i) Pd – Cr synergy, (ii) electron transfer from Pd to Cr and Pd-NH2 interaction, (iii) higher Pd impregnation capacity on NH2-Cr-MOF, and (iv) reduced nanoparticle sizes on the functionalized support.