Highly Stable N-Doped Carbon-Supported Pd-Based Catalysts Prepared from Biomass Waste for H₂ Production from Formic Acid

Abstract

Excellent Pd supported on carbon catalysts for the dehydrogenation of formic acid were synthesized from a lignocellulosic biomass residue. The preparation of the carbon support consisted of a H 3 PO 4 -assisted hydrothermal carbonization (HTC) and activation of a hemp residue and subsequent nitrogen functionalization. It was observed that the presence of nitrogen groups influenced both the size and the electronic properties of the Pd nanoparticles, which ultimately affected their catalytic properties. Furthermore, the catalytic performance also depended on the synthesis conditions used in the preparation of the catalysts (i.e., reduction of the Pd nanoparticles with NaBH 4 prior to the catalytic test or in situ reduction). The best-performance catalysts (Pd/N-HTC (n.r.)), which were prepared by in situ reduction of the nanoparticles, displayed a remarkable catalytic activity with a very high TOF number of 8365 h −1 (TOF value calculated for the 2nd catalytic run and expressed per surface Pd atom) and outstanding stability during 6 consecutive reaction cycles, although the initial activity is maintained for 12 cycles. The catalytic system studied is among the most stable ever reported Pd-based heterogeneous catalysts for the dehydrogenation of formic acid.

H2 Production from Formic Acid Using Highly Stable Carbon-Supported Pd-Based Catalysts Derived from Soft-Biomass Residues: Effect of Heat Treatment and Functionalization of the Carbon Support

“…In this line, the total volume of gas generated after 30 min of reaction per gram of catalysts followed the order Pd/BC < Pd/N-BC < Pd/N-BC_TT < Pd/BC_TT, with a total volume of gas per gram of catalyst of 338, 407, 667, and 771 mL gas .g cat −1 , respectively. The comparison of the catalysts based on non-heat-treated supports (Pd/BC and Pd/N-BC) is in good agreement with previous studies, in which the beneficial effect of N-containing carbon-based catalysts in enhancing the catalytic performance towards the dehydrogenation of FA has been shown [ 31 , 32 , 33 ].…”

“…Pd-based catalysts were synthesized by a wet impregnation method with Pd(OAc) 2 as the metal precursor and suppressing the reduction step [ 32 ]. Briefly, the carbon support was dispersed in a specific volume of acetone, and an aqueous solution of 0.01 M Pd(OAc) 2 was added to obtain Pd-based catalysts with a Pd content of 1 wt.%.…”

“…), while the potential of tailoring the properties of the carbon support is frequently disregarded. The modification of the carbon materials that have been considered lies in the incorporation of nitrogen functional groups, which have been proven to both modify the properties of the metal active phases and participate actively in the dehydrogenation reaction [ 31 , 32 , 33 , 34 ].…”

“…We have previously observed that such a modification of the carbon support by introducing nitrogen atoms serves as a good strategy to obtain highly stable Pd-based catalysts for the production of hydrogen from FA [ 32 ]. However, aside from the incorporation of nitrogen species, very little has been discussed about other characteristics of the carbon supports that may also contribute to achieving enhanced catalytic performances.…”

Ru Catalysts Supported on Commercial and Biomass-Derived Activated Carbons for the Transformation of Levulinic Acid into γ-Valerolactone under Mild Conditions

“…The carbon materials used as supports to prepare the Ru/C catalysts are two commercial activated carbons from MeadWestvaco (now Ingevity Corporation, North Charleston, SC, USA), named SA-30 and WV-1100, and two activated carbons prepared from biomass residues by activation with phosphoric acid (H 3 PO 4 ). ASC was prepared by hydrothermal carbonization from almond shells in conditions, such as those reported in [50]. Milled almond shells were mixed with an aqueous H 3 PO 4 solution (25 wt.%) in a stainless-steel autoclave (H 3 PO 4 /almond shell wt.…”