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The effects of adding Mn and Na promoter metals to graphene oxide (GO)-supported iron-based catalysts for Ficher-Tropsch Synthesis (FTS) reactions to olefins at 20 bars were investigated in a 3D-printed stainless steel (SS) Microreactor. While promoter metals encourage reduction of iron oxide to iron to form iron carbide, the active metal catalysts in GO allow hydrogenation of CO. These catalysts were synthesized by layer deposition method and characterized by different techniques. The TEM images show the integration of graphene oxide into the catalysts. The XRD and XPS studies confirmed the crystal structure and oxidation states of the metals. The catalytic activity and product selectivity were studied in the temperature range of 200–350°Cwith a 2:1 M ratio of H2: CO. Higher CO conversion with greater selectivity for olefins was observed in the presence of the promoters. FeMnNa@GO showed better stability than both Fe@GO and FeMn@GO catalysts in time-on-stream studies. 

Ni/SBA-15 meso-structured catalysts modified with chromium and CeO2 (Ni–Cr-CeO2/SBA-15) were utilized to produce hydrogen from glycerol steam reforming (GSR). The catalysts were synthesized by a one-pot hydrothermal process and extensively characterized by analytical techniques such as N2 adsorption–desorption (BET), H2-temperature programmed reduction (H2-TPR), powder X-ray diffraction (PXRD), inductively coupled plasma-optical emission spectrometry (ICP-OES), and transmission electron microscopy (TEM). The low-angle XRD reflections affirmed that the catalysts were crystalline and possessed a 2D-ordered porosity. The BET results depicted that all the catalysts exhibited a good surface area ranging from 633 to 792m2/g, and the pore sizes were consistently in the mesoporous range (between 3 and 5 nm). TEM analysis of both calcined and spent catalysts revealed that the metal active sites were embedded in the hybrid CeO2-SiO2 support. Overall, the Ni-based catalysts exhibited higher glycerol conversion -12Ni-SBA-15–99.9%, 12Ni3CeO2-SBA-15–89.4%, and 8Ni4Cr3CeO2-SBA-15–99.7%. Monometallic 12Ni/SBA-15 performed exceptionally well, while 12Cr/SBA-15 performed poorly with the highest 71.48% CO selectivity. For short-term GSR reactions, CeO2 addition to 12Ni/SBA-15 did not have any effect, whereas Cr addition resulted in a 32% decrease in H2 selectivity. The long-term stability studies of 12Ni-SBA-15 showed H2 selectivity of ~ 64% and ~ 98% glycerol conversion. However, its activity was short-lived. After 20–30 h, the H2 selectivity and conversion dropped precipitously to 40%. The doping of mesoporous Ni/SBA-15 with Cr and CeO2 remarkably enhanced the long-term stability of the catalyst for 12Ni3CeO2-SBA-15, and 8Ni4Cr3CeO2-SBA-15 catalyst which showed ~ 58% H2 selectivity and ~ 100% conversion for the entire 60 h. Interestingly, Cr and CeO2 seem to improve the shelf-life of Ni-SBA-15 via different mechanistic pathways. CeO2 mitigated Ni poisoning through coke oxidation whereas Cr bolstered the catalyst stability via maintaining a well-defined pore size, structural rigidity, and integrity of the heterogeneous framework, thereby restricting structural collapse, and hence retard sintering of the Ni active sites during the long-term 60 h of continuous reaction. Hydrogen generation from renewable biomass like glycerol could potentially serve as a sustainable energy source and could substantially help reduce the carbon footprint of the environment