The electrochemical conversion of CO₂ into value-added chemicals presents an environmentally sustainable alternative to conventional fossil-derived processes, yet achieving high selectivity remains challenging due to competing reaction pathways. Here, we demonstrate precise tuning of CO₂ electroreduction pathways through femtosecond laser-driven surface doping of Cu with targeted metals, achieving Faradaic efficiencies of 58.9% for CO, 67.9% for formate, and 37.8% for ethylene. This spatially shaping laser technique enables nanoscale deposition of any metal (including Sb, Sn, Re, La, In, Co, Ni, Ag, and Pt) onto Cu foil, forming compositionally graded Cu-based bimetallic surfaces with controlled atomic ratios. Systematic electronic structure analysis reveals that secondary metals induce d-band center shifts spanning −0.21 to +0.78 eV, governing intermediate adsorption energetics-upward shifts strengthen *CO binding via enhanced back-donation, while downward shifts generally weaken adsorbate interactions. Through precise control of Cu/Sn and Cu/Sb atomic ratios, we manipulate electronic structures of CuSn and CuSb catalysts and consequently demonstrate continuous tuning of formate (19.0%–67.9%) and CO (18.8%–58.9%) selectivity. In-situ Raman spectroscopy and valence band X-ray photoelectron spectroscopy (XPS) elucidate dual modulation mechanisms. Sn enhances CO desorption by weakening *CO adsorption, whereas La promotes ethylene formation through optimized CO absorption and dimerization. The tunability of the reaction pathways aligns with metal-dependent stabilization of critical intermediates (CO and *OCHO). This work introduces a nanoscale-depth and trace-level multi-elemental loading strategy with tunable ratios on copper electrodes, enabling precise electronic structure manipulation of Cu-based electrocatalysts to mechanistically elucidate the correlation between surface electronic states and product selectivity, offering a roadmap to design and modulate Cu-based catalysts for selective CO₂-to-chemical conversion and beyond via low-cost laser processing techniques.

Elucidation of a physicochemical process on nanocatalysts, especially under continuously evolving conditions, is often heavily tool-driven because of technical challenges. Recently, ambient pressure X-ray photoelectron spectroscopy (APXPS) emerges as an emerging photon-in-electron-out technique in in-situ/operando analysis by bridging the pressure-gap between conventional ultra-high vacuum (UHV) and near ambient or even close to operating conditions, rendering the advancement of XPS from a UHV-based technique to a versatile and powerful tool that enables the specific probe of numerous events taking place at the gas–solid, liquid–solid and liquid–gas nanoscale interfaces which are critical to nanocatalysis research. For example, APXPS probes information on catalytically active phase and reaction kinetics in nanocatalytic processes; details inside the electric double-layer at an electrolyte/electrode interface can now be accessed; more efficient nanocatalyst design can be achieved and energy transfer venues can be optimized. Here, we aim to critically review the recent advances in instrumentation and the probe of the gas–solid, liquid–solid, and gas–liquid nanoscale interfaces using APXPS-based methodologies, followed by putting forward an outlook of the development of APXPS as a rising in-situ/operando analytical means in surface science, nanocatalysis, nanoscience and materials science.