Generally, the low electron–hole separation efficiency of covalent organic frameworks (COFs) prevents their catalytic performance from reaching satisfactory results. For this reason, the creation of heterojunctions is considered an effective strategy but usually suffers from dimensional mismatch of the integrated material, even at the expense of its redox capacity. To overcome these difficulties, a novel 2D/2D S‐scheme heterojunction between H₂N–Cu–MOF (NCM) and TpPa–1–COF (TP1C) is successfully constructed for efficient photocatalytic H₂ production. The matching dimensions of two crystalline porous materials enables the integrated materials with abundant surface reactive sites, strong interaction and optimized electronic structure. Moreover, the combination of two crystalline porous materials can also form a S–scheme heterojunction, which can not only promote the separation of electron–hole pair, but also preserve the redox ability, thus remarkably boosting the catalytic competence. Consequently, the rate of optimal 20% NCM/TP1C in photocatalytic H₂ production reaches 4.19 mmol g⁻¹ h⁻¹, which is 46.5 times higher than that of bare NCM, and 22.1 folds over that of pure TP1C. This research offers an innovative perspective for the formation of S–scheme heterojunctions based on porous crystal materials for efficient solar energy utilization.

Metal–organic frameworks (MOFs) face significant challenges in photocatalysis due to severe carrier recombination. Here, a novel approach is presented that incorporates ─NH₂ groups and Cu ions onto MOFs with a MIL‐125 skeleton, forming NH₂‐MIL‐125 and Cu‐NH₂‐MIL‐125. This modification effectively enhances the polarity of MOFs, evidenced by significantly increased d₃₃ values (from 1.69 to 26.21 pm/V) and notable higher dipole moments (from 6.60 to 25.99 D). Notably, it's the first demonstration of boosting MOFs piezoelectricity via a dual modulation strategy. Moreover, the polarity can be further amplified by ultrasonic vibration based on the positive piezoelectric effect, which is justified by in situ Raman spectra, COMSOL simulations, and DFT calculations, by taking into account the applied pressure. The positive impact of introduced piezoelectric effect in facilitating charge separation and transfer of Cu‐NH₂‐MIL‐125, proved by enhanced current response. Consequently, through coupling piezocatalysis and photocatalysis, the H₂ production rate of Cu‐NH₂‐MIL‐125 can be significantly enhanced to ≈2884.2 µmol·g⁻¹·h⁻¹, 2.76 and 9.92 times higher than that of NH₂‐MIL‐125 and MIL‐125, respectively, ranking first in all reported MOF‐based piezo‐photocatalysts. This research demonstrates the prospective opportunity for alleviating the severe carriers recombination problem for MOFs through the implantation of piezoelectric field driving force.

2D covalent organic frameworks (COFs) are considered as one kind of the most promising crystalline porous materials for solar‐driven hydrogen production. However, adding noble metal co‐catalysts into the COFs‐based photocatalytic system is always indispensable. Herein, through a simple solvothermal synthesis method, TpPa‐1‐COF, a typical 2D COF, which displays a wide light absorption region, is rationally combined with transition metal phosphides (TMPs) to fabricate three TMPs/TpPa‐1‐COF hybrid materials, named Ni₁₂P₅ (Ni₂P or CoP)/TpPa‐1‐COF. The incorporated TMPs can be served as electron collectors for accelerating the transfer of charges on TpPa‐1‐COF, thus the composites are demonstrated to be efficient photocatalysts for promoting water splitting. Benefitting from the richer surface reactive sites and lower H* formation energy barrier, the Ni₁₂P₅ can most effectively improve the photocatalytic performance of the TpPa‐1‐COF, and the H₂ evolution rate can reach up to 31.6 µmol h⁻¹, approximately 19 times greater than pristine TpPa‐1‐COF (1.65 µmol h⁻¹), and is comparable to the Pt/TpPa‐1‐COF (38.8 µmol h⁻¹). This work is the first example of combining COFs with TMPs to construct efficient photocatalysts, which may offer new insight for constructing noble‐metal‐free COF‐based photocatalysts.