**4.2 Other metallic alloys**

Although copper gained a lot of attention for hydrocarbon production through electrochemical reduction of CO2, some other metallic alloys have also shown to be quite noteworthy for this application. For example, Lewis and co-workers reported nickel–gallium alloys of different compositions prepared by drop-casting and a subsequent temperature-programmed reduction method [69]. The alloy foil was slightly enriched in zinc both at the surface and in the bulk, with a surface alloy composition of 61.3 at% zinc and a predominantly Ag5Zn8 bulk phase. The FECH4 values at 1.43 V vs. RHE were five times and three times higher with the alloys than those produced at pure Ag and Zn electrodes, respectively.

The summary of some recent reports for C1+ hydrocarbons are being reported in **Table 3**.

As for the possible pathways for electrochemical reduction of CO2 to hydrocarbons, In an attempt to elucidate the mechanism of CO2 reduction, it was found


#### **Table 3.**

*C1+ hydrocarbon selective electrocatalyst.*

**Figure 3.** *Schematic of possible pathways for methane production.*

*Heterogeneous Electrocatalysts for CO2 Reduction to Value Added Products DOI: http://dx.doi.org/10.5772/intechopen.97274*

that CO is a key intermediate in the formation of CH4 and C2H4 [79] and that the products of CO2 reduction reaction depend on the metal's binding energy to CO [80]. Based on these findings, one strategy for efficient electrochemical CO2 conversion is to separate the process into two steps: CO2 reduction to CO, followed by CO reduction to oxygenates and hydrocarbons [81]. The schematic of the possible pathways toward methane production has been illustrated in **Figure 3**.
