Electrocatalytic n-valeraldehyde oxidation reaction was an inexpensive and eco-friendly method to control n-valeraldehyde contamination and produce high value-added octane. However, low-cost and readily available electrocatalysts with high current efficiency were urgently needed. Herein, two-dimensional porous carbon derived from pollen with enlarged interlayer distance was built by alkali activation method, applying in electrocatalytic n-valeraldehyde oxidation reaction. The enlarged interlayer distance was verified by X-ray diffraction (XRD) and high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM). Electrocatalytic experiments consequences showed activated biomass derived carbon possessed a higher electrocatalytic activity and octane selectivity than unactivated catalyst. Systematic tests and in situ infrared experiments demonstrated that enlarged interlayer distance was positively correlated with specific surface area of catalysts, large specific surface area provided abundant absorption sites, facilitated the adsorption for n-valeraldehyde, and further promoted the transformation of n-valeraldehyde to octane. This work also provides a new avenue for creating high-performance electrocatalysts in terms of lattice engineering.