| Ce Tailored Co-Ni/Htlc | Co-precipitation, calcination and finally incipient wetness impregnation for Ce promotion | 500˚C & 0.1 MPa | Excellent H2 productivity, better CO2 adsorption capacity, good stability and inhibited coke formation | The activity of the catalyst degrades after a certain regeneration cycle due to metal sintering | 90 | [79] |
| Hydrotalcite (Htlc)-based Ni with Ag | Co-precipitation followed by reduction and calcination at 600˚C for 6 h | 670˚C & atmospheric pressure | Ni/Ag hydrotalcite catalyst has good surface alloying | Sites surrounding Ag atom found to be inactive to C-H bonds of CH4 and Ag blocked the more active sites in Ni nanoparticles | - | [76] |
| Ce- and Zr-doped Ni/ hydrotalcite | Co-precipitation, calcination and then incipient wetness impregnation for Zr & Ce promotions | 673 - 873 K & 0.1 MPa pressure | Ce and Zr promoted Ni/hydrotalcite catalyst produced high purity H2 with good stability | Zr promoted catalyst has lower stability then Ce promoted one | 97.1 | [93] |
| Ni/Mg-Al | Co-precipitation and then calcination at 850˚C for 5 h | 650˚C & 0.1 MPa Pressure | Ni/Mg-Al catalyst exhibited better catalytic performance than the conventional Ni/a-Al2O3 and Ni/g-Al2O3 catalyst | CO2 selectivity decreased with rising temperature | - | [94] |
| Ni-Htlc catalyst and Ni-CaO/Al2O3 Sorbent | Co-precipitation & calcination for catalyst and incipient wetness impregnation for sorbent | 523 K & 0.1 MPa pressure | Catalysts were viable for high purity H2 production and have high stability | Ni-Htlc catalyst showed short breakthrough time and lower adsorption capacity | 98.5 | [95] |
| Ni/MgAl + CrFe3O4 | Dry impregnation followed by drying and calcination at 500˚C for 5 h | 500˚C - 700˚C & 1 bar pressure | Ni/MgAl + Cr/Fe3O4 mixed catalyst exhibited improvedH2 selectivity and CH4 conversion | Catalysts showed a rapid decrease in H2 selectivity and CH4 conversion with the decrease of temperature | - | [96] |
| Ni and/or Rusupported hydrotalcite material | Incipient wetness impregnation, then drying and calcination for 5 h at 400˚C | 700˚C & 1 bar pressure | The catalysts showed higher methane conversions that are almost similar to the values predicted by thermodynamic equilibrium and better resistance to carbon deposition | At high space velocities, the product gas seems to has more obstacles in reaching thermodynamic equilibrium | - | [97] |
| Ru/Ni-Mg/Al | Wet impregnation of co-precipitated Ni-Mg/Al Htlc for Ruincorporation | 450˚C - 800˚C | Catalysts with Ru (ruthenium) were active with no need reduction pretreatment before the test and the catalyst showed better catalytic performance | The surface area of the support decreased with Rh impregnation | - | [98] |
| Ni-Htlc + Calcium Aluminate | Co-precipitation & calcination for Ni-Htlc and pelletization of Ca-based sorbent | 550˚C | The catalyst mixture produced high purity H2 | Only the effect of sorbent addition was studied | 99 | [99] |
| Ni/CaO- Hydrotalcite | Incipient wetness impregnation, then drying and calcination at 900˚C for 4 h | 400˚C - 600˚C | High H2 concentration of 80% was achieved at low temperature (600˚C) | The developed catalyst showed less activity than Ni/Al2O3 catalyst | 80 | [100] |
| Pt/Htlc (Ni-Mg-Al) | Wet impregnation of calcined Mg/Al-Htlc for Ni and Pt doping | 700˚C | Pt-Ni alloying on the surface of the catalyst caused self-regeneration and self-activation via reversible redox between Ni˚ and Ni2+ by H2 spillover from Pt | CH4 conversion over the developed catalyst was not compared precisely | - | [101] |