本研究採用非計量比Ti含量提升與Cr摻雜之協同設計方法，製備Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅與Ti₁.₃Fe₀.₉Cr₀.₁兩種TiFe基儲氫合金，分別探討成分設計對微結構特徵、儲氫熱力學性質及抗雜質毒化能力之影響。微結構分析結果顯示，Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅及Ti₁.₃Fe₀.₉Cr₀.₁試片因Cr的固溶置換使主相晶格常數由2.9760 Å(純TiFe相)分別膨脹至2.9829 Å及2.9935 Å，此晶胞膨脹效應有助於擴增氫原子進入晶格的間隙空間；此外，兩者試片皆含微量Ti₂Fe二次相(約1%)，以上兩種結構有利於提升TiFe基室溫活化能力。 雜質氣體循環老化測試結果顯示，兩種合金在200 ppm 的N₂、O₂、CO₂及CO雜質氣體環境下的毒化強度排序一致為CO ≥ CO₂ > O₂ > N₂。其中對於Ti₁.₃Fe₀.₉Cr₀.₁合金而言，N₂對儲氫性能影響最為輕微，30次循環後衰退率僅約14%、；O₂環境下的衰退率49.6%、，顯著優於Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅合金的62.0%、，顯示Cr元素具有保護TiFe主相的效應；CO₂與CO則分別造成約85%與95%的嚴重性能衰退，結果證實Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅及Ti₁.₃Fe₀.₉Cr₀.₁兩種合金均難以抵抗其雜質對合金的毒化效應。Ti1.3Fe0.9Cr0.1試片在CO₂與CO雜質氣體老化測試後的XRD繞射圖譜經由Rietveld精修分析，合金內部殘留大量β-TiFeHₓ與γ-TiFeH₂氫化相，其根源在於雜質分子在氫化相變化過程中包覆合金表面，阻斷脫氫路徑、。最後，本研究成果與國際間比較、，非計量比Ti含量提升與Cr摻雜的協同方法些微改善TiFe合金的活化性能與抗O₂及CO2之毒化能力。;In this study， a synergistic design approach combining off-stoichiometric Ti enrichment and Cr doping was adopted to fabricate two TiFe-based hydrogen storage alloys， Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ and Ti₁.₃Fe₀.₉Cr₀.₁， with the aim of systematically investigating the effects of compositional design on microstructural characteristics， hydrogenation thermodynamic properties， and resistance to impurity poisoning. Microstructural analysis revealed that due to Cr substitution， the lattice parameters for the primary phase of the Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ and Ti₁.₃Fe₀.₉Cr₀.₁ samples expanded from 2.9760 Å (pure TiFe phase) to 2.9829 Å and 2.9935 Å， respectively. This unit cell expansion effect facilitates the enlargement of interstitial sites for hydrogen atoms to enter the lattice. Furthermore， both samples contained a trace amount of a secondary Ti₂Fe phase (approximately 1%). Both of these structural characteristics are beneficial for enhancing the activation capability of the TiFe-based alloys at room-temperatures. Cyclic hydrogenation tests under 200 ppm impurity gas demonstrated that both alloys exhibited a similar poisoning severity ranking of CO ≥ CO₂ > O₂ > N₂. For the Ti₁.₃Fe₀.₉Cr₀.₁ alloy， N₂ showed the mildest impact on hydrogen storage performance， with a capacity degradation rate of only about 14% after 30 cycles. Under O₂ exposure， the hydrogenation degradation rate was 49.6%， which is significantly better than that of the Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ alloy (62.0%)， indicating a protective effect of the Cr element on the TiFe matrix. CO₂ and CO， however， caused severe hydrogenation degradation of approximately 85% and 95%， respectively， indicating that both the Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ and Ti₁.₃Fe₀.₉Cr₀.₁ alloys were unable to resist the poisoning effects of these impurities. Rietveld refinement analysis of the XRD patterns for the Ti₁.₃Fe₀.₉Cr₀.₁ sample after CO₂ and CO impurity gas cyclic tests revealed that substantial amounts of residual β-TiFeHₓ and γ-TiFeH₂ hydride phases were retained within the alloy. The main reason of this is that impurity molecules encapsulated the alloy surface during the phase transformation of metal hydrides， thereby blocking the dehydrogenation pathways. Finally， compared with international studies， the results of this research demonstrate that the synergistic approach of off-stoichiometric Ti enrichment and Cr doping slightly improves the activation performance and the resistance to O₂ and CO₂ poisoning of TiFe-based alloys. Keywords: TiFe-based hydrogen storage alloy， non-stoichiometric， Chromium doping， Impurity poisoning， Cyclic degradation， Activation behavior
