Nickel-based catalysts comprising silicon modified nickel (nickel silicate) are provided, as are methods for using the catalysts to i) convert methane to CO and H2 (e.g. for use in synthetic chemical compound production); or to ii) convert methane to oxygenated hydrocarbons e.g. one or more of methanol, acetone, formaldehyde, and dimethyl ether. The catalysts are bifunctional and comprise both Ni metallic catalytic sites and acidic nickel-silicon catalytic sites, and the conversions are performed under moderate reaction conditions.