Producing synthesis gas from greenhouse gases has become an interesting and challenging subject in the face of issues like global warming and its undesirable consequences . Dry reforming of methane (DRM) is the main process of producing synthesis gas with a molar ratio of one. An advantage of using this method is the high purity of the generated CO . The synthesis gas prepared through DRM can be used in producing methanol and dimethyl ether (C2H6O) as well as in Fischer-Tropsch process and carboxylation . Carbon deposition is the major problem in the DRM process. The two reactants in this process – namely CO2 and methane (CH4) – contain carbon, which is deposited as a result of the reaction leading to catalyst deactivation [4–5].To date, numerous studies have explored the performance of noble and non-noble metals in DRM. The results suggest that although noble metals are highly resistant to carbon deposition, their large scale use is not economical due to their high expenses. On the other hand, non-noble metals like Nickel (Ni) demonstrate enhanced and more economical catalytic activity at the expense of higher carbon deposition [6–7]. Due to methane decomposition and the Boudouard reaction in DRM, such catalysts are more susceptible to coke formation, hence reducing catalyst stability to some extent [8–10].Since using support in the DRM process plays a critical role in boosting catalytic activity and minimizing carbon deposition, Gamma-alumina (γ-Al2O3) is utilized in many cases as the support for nickel-based catalysts [11, 12, 13]. Various studies have investigated ways to improve the performance and stability of Ni/Al2O3 as well as its resistance to coke formation, with the findings indicating the effectiveness of adding promoters [14, 15, 16].Among different promoters used for nickel-based catalysts, zirconium dioxide (ZrO2) and cobalt (Co) have received special attention [17–19]. Adding an appropriate amount of Co results in strong metal-support interaction, reduces particle size, and improves resistance to coke formation, thus enhancing catalytic activity [20–21]. Research has displayed that using a combination of Ni and Co as the catalyst, with the proportion of the latter ranging from 3–5%, yields acceptable performance . On the other hand, given its good oxidation-reduction and oxygen mobility properties, ZrO2 increases the dispersion of carbon and facilitates its gasification, hence preventing carbon deposition. Moreover, ZrO2 hinders the entrance of the active phase into alumina structure and active spinel phase development (NiAl2O4) [22–23]. This promoter is also recognized as an acid-base bi-functional catalyst since CO2 is an acid gas and requires a base site to be adsorbed on the catalyst surface. Therefore, ZrO2 can function as a base catalyst in DRM, increasing CO2 adsorption . It has been demonstrated that using a 10% weight ratio of ZrO2 in the support can yield catalyst’s optimum performance in DRM . Sharifi et al.  explored the impact of sol-gel method and the inclusion of Co and copper (Cu) promoters on the performance of Ni/Al2O3-ZrO2 catalyst in a fixed bed reactor. The results showed that adding promoters, especially Co, to Ni/Al2O3-ZrO2 nanocatalyst led to particle size reduction and uniformity in nanocatalyst dispersion. It was also found that adding Co would improve feed conversion, product efficiency, and the ratio of synthesized gas. The researchers discovered that, during the 1440-minute test, Ni/Al2O3-ZrO2 synthesized by the sol-gel method had the highest performance when the temperature was 850°C. Since in the fixed-bed reactors the catalytic particles have various sizes and are randomly dispersed on the bed, the reactants register uneven access to the catalyst surface. This leads to the formation of uneven flow patterns and the formation of hot spots and high thermal gradients in exothermic reactions, hence significantly undermining the reactor’s performance. To eliminate the problems associated with fixed-bed reactors, structured reactors have been introduced as valuable alternatives in different processes . Microchannel reactors constitute one specific type of structured reactors. One of the major features of microchannel reactors is their high surface area to volume ratio. Thus, they are expected to be highly efficient in terms of thermal performance. The main advantage of this phenomenon is the rise of operating temperature and reaction conversion. In other words, exploiting reactors that are smaller in volume and require lower amounts of catalyst does not make any change in the amount of conversion. Yet, their smaller size results in less energy consumption and lower operating costs . In another study, Kim et al.  designed a microreactor system and explored its efficiency and stability in partial oxidation of DME for hydrogen production. Its performance was then compared with that of a conventional pack bed reactor. The microchannel reactor had a thin layer of Al2O3 as catalyst support on the surface of the microreactor, while, in the fixed-bed reactor, Al2O3 balls were densely packed in a quartz tube. Using enough amounts of catalyst (0.5% wt Ru), both reactors demonstrated similar degrees of conversion. Declining the amount of Ru, however, resulted in reduced efficiency in the conventional fixed-bed reactor, whereas the efficiency of the microchannel reactor remained intact. Sangsong et al.  synthesized two Ni-based catalysts – namely 10 wt.% Ni/MgO and 10 wt.% Ni/Al2O3-MgO – using sol-gel method. Both catalysts were applied in DRM as catalyst pellets and catalyst-coated plates. The results showed significant decline in carbon deposition when the catalyst was coated as a thin film on the microreactor plate. Mahmoudizadeh et al.  explored the performance of methanol steam reforming in a microchannel and a fixed-bed reactor, with the findings displaying significantly higher amounts of methanol conversion in the microchannel reactor. The researchers attributed this to the reactants’ better access to the active sites. Concentrating on the amount of catalyst coating, Bawornruttanaboonya et al.  compared autothermal biogas reforming over a Re-Ni/Al2O3 catalyst in a split-and-recombine microreactor with that of a conventional reactor. In particular, they examined the influence of various inlet feeds and temperatures in an attempt to figure out the optimum condition. In all cases, the highest amount of CH4 and CO2 conversion, the lowest concentration of H2O, and the lowest degree of hot spot formation were registered in the split-and-recombine microreactor. Rezaei et al.  investigated the performance of DRM in a researcher-designed microchannel reactor using an Ni/Al2O3 catalyst coated on a stainless steel plate via sputtering method. Since in a microchannel structure a thin film of the catalyst covers the metal surface, the reactor shows a much lower pressure drop in comparison with the time a fixed-bed reactor is used . In general, irrespective of the method used for catalyst coating, the catalyst features (e.g., crystallite phases, morphology, and active phase dispersion) must be retained. Additionally, the selected method should provide uniform coating, desirable catalyst loading, and suitable adhesion . Physical vapor deposition (PVD) is a novel method for coating various materials. Using this method, thin films can be physically coated over the substrates. Coatings produced through PVD can also be utilized with different metallic parts at various temperatures. PVD can assist in creating durable and high quality uniform coatings which are economical as well . The current study was an initial attempt to examine the optimum performance of an Ni-Co/Al2O3-ZrO2 catalyst in a microchannel reactor using PVD for catalyst coating. To this end, the Box-Behnken design (BBD) was adopted to study the impact of various parameters (i.e., coating time, Co/Ni weight percentage, and reaction temperature at three levels) on initial feed conversion, CO2 and CH4), H2:CO molar ratio, and catalyst stability with the aim of identifying the optimum condition.