Physical and Chemical Characterization: Powder X-ray diffraction (PXRD, Bruker D8 Venture) was measured on powder samples in Kapton capillaries with Cu K𝛼 radiation. X-ray photoelectron spectroscopy (XPS, PHI Versaprobe 3) was performed with Al K𝛼 radiation with electron and ion neutralization and pass energies of 55 eV for C and N and 225 eV for survey scans and additional Ni scans. Ni K-edge X-ray absorption spectroscopy (XAS, BL 11-2, SSRL, SLAC National Accelerator Laboratory) was performed on powders adhered to Kapton tape with fluorescence detection using a 100-pixel solid state Ge detector. The incident beam was monochromated by a Si (220) liquid-nitrogen cooled double-crystal monochromator with the energy axis calibrated by the first inflection point of a downstream nickel foil set to 8333 eV. Data was collected between 8100 eV and 9200 eV. For EXAFS data, Fourier-transforms were performed with a k-range of [2 Å -1 8 Å -1 ] with k 2 weighting. No time-dependent spectral changes were observed with a repeated data collection.